Roulette
Roulette is a popular casino gambling game in which players place bets on a numbered wheel divided into red and black pockets, with a croupier spinning the wheel in one direction and a small ball in the opposite direction until the ball comes to rest in one of the pockets, determining the winning bets.[1] The game features two primary variants: European roulette, which uses a wheel with 37 pockets numbered 0 through 36, and American roulette, which adds a double zero (00) for a total of 38 pockets, increasing the house advantage.[1][2] The origins of roulette trace back to 18th-century France, where it emerged in Parisian casinos around the mid-1700s as a combination of earlier wheel-based games and number betting, though fanciful claims of invention by mathematician Blaise Pascal in the 17th century have been widely debunked.[1][2] It quickly gained popularity across Europe but faced bans in France from the 1830s onward due to gambling restrictions, leading to its spread to other regions including Monte Carlo and eventually the United States in the 19th century, where the American double-zero version developed to boost casino profits.[2] Players bet by placing chips on a layout corresponding to wheel sections, with inside bets targeting specific numbers or small groups (such as straight-up on a single number or split on two adjacent) offering higher payouts up to 35:1, and outside bets on broader categories like red/black, odd/even, or high/low providing even-money returns but lower risk.[1][3] Mathematically, roulette is a game of independent trials governed by probability, where the chance of the ball landing on any single number is 1/37 in European roulette (approximately 2.70%) and 1/38 in American (approximately 2.63%), but the house edge arises from the zero(s) not being covered in even-money bets, resulting in an overall advantage of 2.70% for European and 5.26% for American versions.[1][3] This edge ensures long-term profitability for casinos, as the law of large numbers dictates that outcomes converge to these probabilities over many spins, making strategies like the Martingale system ineffective against the inherent odds despite their popularity among players.[2][1]History
Origins in Europe
A common but debunked myth attributes the origins of roulette to the French mathematician Blaise Pascal in the 17th century, stemming from his experiments with perpetual motion machines. However, no historical evidence supports this claim, and roulette emerged in 18th-century France as a combination of earlier wheel-based games.[1][2] Roulette's development in Europe drew significant influence from earlier wheel-based games prevalent in 17th- and 18th-century France and Britain, such as Roly-Poly and Even-Odd. Roly-Poly, documented as early as the 1720s, involved a wheel with sections for even and odd outcomes plus a central "bank" pocket that favored the house, while Even-Odd simplified betting to parity with similar mechanics; these games introduced the concept of a spinning wheel and ball for random outcomes, blending with Italian lotteries like Biribi to form roulette's hybrid structure. The innovation of zero pockets created a house edge by ensuring not all bets paid even money, transforming informal pastimes into structured gambling. Early European wheels included both single zero (0) and double zero (00), with the single-zero configuration introduced later in 1843.[4][5][6] The first recorded appearances of roulette in French casinos occurred in the mid- to late 18th century, with primitive wheels used in illicit gaming houses despite periodic bans, and the first documented wheel appearing around 1796. By the late 18th century, the game gained formal traction in Paris, with official rules codified around 1796 at establishments in the Palais Royal, including standardized betting options and the wheel layout that evolved into modern variants. This period solidified roulette's place in French high society, where it was played in salons and early casinos, blending chance with elegance before spreading further across the continent.[7][8][4]Evolution and Spread
Following its emergence in 18th-century French salons, roulette began to evolve and spread across Europe in the mid-19th century. In 1843, brothers François and Louis Blanc introduced a single-zero roulette wheel at the casino in Bad Homburg, Germany, removing the double zero to offer better odds to players and attract gamblers away from competing establishments in Paris.[9] This innovation helped popularize the game in German spa towns, where it became a staple of upscale entertainment.[4] The Blanc brothers further propelled roulette's dissemination when gambling was banned in Germany in the 1860s, leading them to relocate to Monte Carlo, Monaco, in 1863. There, they took over the struggling Casino de Monte-Carlo and implemented the single-zero variant, which boosted the casino's fortunes and established European roulette as the dominant form on the continent.[10] Meanwhile, across the Atlantic, French immigrants brought an earlier double-zero version of the game to New Orleans in the early 19th century, where it thrived in the city's vibrant gambling scene along the Mississippi River.[11] This adaptation, known as American roulette, incorporated the additional double zero to increase the house edge, distinguishing it from the European style and solidifying its place in U.S. gaming culture.[12] In the United States, roulette's growth faced setbacks from anti-gambling laws, such as New York's 1908 Hart-Agnew Law, which effectively shut down legal betting venues and race tracks, pushing the game underground or westward toward more permissive regions.[13] The tide turned in 1931 when Nevada legalized casino gambling to revive its economy during the Great Depression, sparking the development of Las Vegas as a gaming hub where roulette quickly became a centerpiece of casino floors.[14] Post-World War II economic prosperity fueled a global casino boom, with roulette spreading to new legalized markets in Europe, Asia, and beyond as international tourism and resort construction proliferated.Modern Variations
The advent of online roulette in the late 1990s marked a significant digital transformation of the game, driven by the proliferation of internet access and the development of random number generator (RNG) software to simulate wheel spins fairly and independently.[4] Early online casinos, such as those launched around 1996, integrated RNG technology to ensure unbiased outcomes, replicating the randomness of physical wheels while allowing players to access the game from personal computers.[15] This innovation expanded roulette's reach beyond land-based venues, with RNG-based versions becoming a staple in virtual casinos by the early 2000s, offering variants like European and American styles with certified fairness through independent audits.[16] Building on this foundation, live dealer roulette emerged in the early to mid-2000s, introducing real-time video streams of professional dealers operating physical wheels to bridge the gap between online convenience and traditional casino immersion.[17] Pioneered by providers like Playtech and Evolution Gaming, these formats utilized broadband internet and webcam technology, allowing players to interact via chat while watching spins from studios in locations such as Latvia and the Philippines.[18] By the late 2000s, live dealer streams had evolved to include multiple camera angles and high-definition video, enhancing player trust and engagement in online platforms.[19] In parallel, modern casinos have introduced compact variants like mini-roulette, which features a wheel with only 13 pockets—numbers 1 through 12 plus a single zero—to accelerate gameplay and appeal to casual players seeking quicker sessions.[20] This version maintains core betting mechanics but adjusts payouts proportionally, such as 11:1 for straight-up bets, and has gained popularity in both land-based and online settings since its development in the early 2000s.[21] Complementing this, multi-wheel roulette variants, such as those with up to eight synchronized wheels, enable simultaneous spins to increase betting volume and excitement, often featured in live dealer formats launched by Evolution Gaming in 2020.[22] These adaptations, including Instant Roulette with 12 auto-spinning wheels, cater to high-volume players while preserving the game's probabilistic integrity.[23] Regulatory frameworks for roulette and online gambling have intensified in the 2020s, with the European Union emphasizing responsible gambling features on platforms to mitigate addiction risks through mandatory tools like deposit limits, self-exclusion options, and behavioral monitoring.[24] EU member states, under directives like the Audiovisual Media Services Directive, require operators to implement age verification and reality checks, with the European Gaming and Betting Association advocating for standardized markers of harm detection in games including roulette.[25] In the United States, the 2018 repeal of the Professional and Amateur Sports Protection Act (PASPA) indirectly spurred state-specific expansions of online casino gambling, legalizing real-money roulette in seven states—Connecticut, Delaware, Michigan, New Jersey, Pennsylvania, Rhode Island, and West Virginia—by 2025, each with tailored rules on licensing, taxation, and player protections.[26] These developments reflect a patchwork of regulations, where states like New Jersey, which launched iGaming in 2013 and expanded post-PASPA, impose geofencing and responsible gaming mandates similar to EU standards.[27] Emerging technologies have further innovated roulette through virtual reality (VR) pilots in casino apps from 2023 to 2025, creating immersive 3D environments where players use VR headsets to interact at virtual tables, spin wheels, and socialize in simulated casinos.[28] Platforms like SlotsMillion and PokerStars VR have integrated VR roulette, allowing avatar-based play with realistic physics and multi-player features, tested in beta releases to enhance engagement while incorporating responsible gambling safeguards.[29] These pilots, often powered by Unity or Oculus software, represent early adoption in regulated markets, with projections for broader integration by 2026 to blend physical and digital experiences.[30]Equipment and Setup
Roulette Wheel Design
The roulette wheel is a precision-engineered device central to the game, consisting of a rotating bowl with numbered pockets designed to ensure fair and random outcomes through balanced construction and uniform components. Traditional wheels feature a wooden or composite bowl that holds the pockets, separated by frets, with a central spindle allowing smooth rotation. Modern designs prioritize durability, resistance to wear, and compliance with gaming regulations to prevent bias.[31] Standard roulette wheels in professional casino settings measure approximately 32 inches in diameter, accommodating either the European single-zero configuration with 37 pockets (numbered 0 through 36) or the American double-zero version with 38 pockets (numbered 0, 00 through 36). The European wheel's pockets alternate between red and black numbers, with the green 0, while the American includes an additional green 00, increasing the house edge. These sizes ensure consistent ball trajectories and are scaled for casino environments, with smaller variants (18-30 inches) used for non-professional play.[32][33] The bowl is typically crafted from high-grade hardwoods like mahogany for aesthetic appeal and stability, though contemporary wheels often use fiberglass-reinforced plastic to enhance longevity and reduce maintenance. Frets, the metal dividers (commonly brass, aluminum, or chrome-plated for non-magnetic properties) between pockets, are scalloped to deflect and slow the ball, promoting randomness by interrupting its spin. Roulette balls, once made from ivory for their smooth roll and rebound, have transitioned to synthetic materials such as Teflon, nylon, or phenolic resin since the mid-20th century to address ethical concerns over elephant ivory and improve fairness through consistent density and reduced wear on the wheel.[34][31][35] To facilitate the ball's path, the wheel incorporates a slight incline in the upper ball track, guiding the ball counterclockwise while the wheel rotates clockwise, eventually causing it to drop into a pocket. Pockets are uniformly dimensioned, elliptically shaped with consistent depth, to capture the ball unpredictably without favoring specific numbers. At least eight non-metallic canoe stops along the track further deflect the ball. Manufacturing adheres to strict standards, including perfect horizontal leveling of the rotor to eliminate bias, secure non-moving parts, and overall non-metallic construction where possible to avoid magnetic interference. Wheels are certified by independent labs such as Gaming Laboratories International (GLI) for uniformity, balance, and tamper resistance, with each unit featuring a unique manufacturer identifier for traceability.[36][37]Table Layout and Components
The roulette table is covered with a standard green baize cloth that forms the primary betting surface, featuring a numbered grid of 1 through 36 arranged in three columns of 12 numbers each, dedicated sections for the zero pocket (in European variants) or double zero (in American variants), and surrounding areas for outside bets including red/black, odd/even, and high/low options.[38] This layout ensures clear separation between inside bets on specific numbers and outside bets on broader categories, with the cloth typically made from durable wool or synthetic felt to withstand repeated use.[39] At the dealer's position, opposite the players' side, the table includes chip racks—such as multi-level holders like the Chipper Champ—for organizing and dispensing casino chips and value chips, along with space for managing the overall layout to accommodate both inside and outside bet placements.[39] A marker known as a dolly, often a small plastic or metal indicator, is positioned by the dealer on the layout to denote the winning number after the ball comes to rest on the adjacent wheel.[39] Key accessories facilitate smooth gameplay, including a rake—a telescoping tool with an acrylic head used by the dealer to sweep away losing bets and chips from the layout—and the aforementioned dolly for result marking; in electronic versions adapted for online play, these elements are digitized, with virtual rakes and markers simulated on interactive screens and player terminals to replicate the physical experience.[40] Roulette tables typically measure 8 feet by 4 feet to provide sufficient space for up to seven players and the dealer, though some casinos employ multi-game tables or electronic stadium setups that incorporate roulette alongside other games like blackjack or baccarat for efficient floor space utilization.[41][42]Number Sequence and Pocket Arrangement
The roulette wheel's number sequence is a deliberate arrangement of 37 pockets in the European version (or 38 in the American), designed to promote randomness and fairness by distributing numbers in a non-sequential order around the circumference. This fixed order ensures that adjacent numbers do not follow numerical progression, instead alternating colors and balancing other attributes to prevent exploitable patterns. The sequence begins with the green zero pocket and proceeds counterclockwise. In European roulette, the standard sequence is: 0, 32, 15, 19, 4, 21, 2, 25, 17, 34, 6, 27, 13, 36, 11, 30, 8, 23, 10, 5, 24, 16, 33, 1, 20, 14, 31, 9, 22, 18, 29, 7, 28, 12, 35, 3, 26.[38] Pockets for numbers 1 through 10 and 19 through 28 are colored red, while 11 through 18 and 29 through 36 are black, creating a strict alternation of red and black around the wheel except for the green 0.[43] Odd and even numbers are distributed such that no more than two of the same parity are adjacent, typically alternating in pairs (e.g., two odds followed by two evens).[44] Similarly, low numbers (1-18) and high numbers (19-36) are interspersed evenly, with roughly equal representation in any given sector, to balance outside bets like red/black, odd/even, and high/low.[43] The green 0 stands ungrouped from these categories, serving as the house advantage without aligning to red, black, odd, even, low, or high.[44] This arrangement originated in the 1840s when French brothers François and Louis Blanc redesigned the wheel for the Bad Homburg casino in Germany, introducing the single-zero version to reduce the house edge from the prior double-zero setup and enhance player appeal.[45] The non-sequential placement specifically aims to eliminate sector bias, where physical imperfections in early wheels could favor clustered numbers; by scattering similar attributes (e.g., all reds or highs), the design makes it difficult to predict or exploit gravitational or manufacturing flaws over short sessions.[44][46] The American roulette wheel modifies this by adding a second green pocket for 00, increasing the total to 38 and raising the house edge to 5.26% on most bets.[43] The sequence starts from 0 and runs counterclockwise: 0, 28, 9, 26, 30, 11, 7, 20, 32, 17, 5, 22, 34, 15, 3, 24, 36, 13, 1, 00, 27, 10, 25, 29, 12, 8, 19, 31, 18, 6, 21, 33, 16, 4, 23, 35, 2, 14.[47] The 00 is positioned between 1 and 27, disrupting the European balance slightly by creating minor clusters (e.g., more consecutive evens in some sectors) and further scattering the color and parity alternations, though it retains the core principle of randomization.[48] This adaptation emerged in the United States in the 19th century, prioritizing higher casino advantage over the purer distribution of the European model.[45]Rules of Play
Basic Gameplay Mechanics
In a standard casino roulette game, players begin by purchasing color-coded chips from the dealer, with the chip value determined by the buy-in amount, typically divided across a set number of chips such as 100 for a full rack.[43] These chips are placed on the betting layout to wager on various outcomes before the dealer initiates the spin, adhering to table-specific minimum and maximum bet limits enforced to manage game pace and house exposure.[49] Players may place multiple bets simultaneously, but all wagers must be finalized prior to the dealer's announcement signaling the end of betting.[50] The dealer, known as the croupier, then spins the roulette wheel counterclockwise while releasing the ball clockwise along the outer track, ensuring the two elements rotate in opposite directions to promote randomness.[51] As the ball's momentum slows and it approaches the pockets, the dealer calls "no more bets" to halt any further chip placements or adjustments, preventing interference with the outcome.[52] This call typically occurs when the ball nears the wheel's deflection area, maintaining fairness and game integrity.[50] Once the ball settles into a numbered pocket, the dealer announces the winning number and its color, marking the result with a layout indicator such as a dolly.[43] Losing bets are immediately cleared and collected by the dealer, while winning bets remain on the layout for payout processing in accordance with standard procedures.[49] The dealer handles payouts methodically, starting from inside bets and moving outward, ensuring all eligible wagers are resolved before the next round begins.[43] For even-money bets (such as red/black or odd/even) on single-zero wheels, special rules apply if the ball lands on zero: under the en prison rule, the bet is "imprisoned" or held for the next spin, returned without winnings if it loses again, or released even if it wins; alternatively, the la partage rule allows players to recover half their stake immediately, with the other half lost.[43] These mechanisms, common in European and French roulette variants, mitigate the house advantage on such outcomes without altering the core spin resolution.[43] A typical roulette turn lasts 45 to 60 seconds from the start of betting to the completion of payouts, allowing for efficient play while accommodating multiple participants.[53] Casino etiquette dictates that players refrain from touching the layout or their chips after the "no more bets" call, respecting the dealer's control and avoiding disputes over wager alterations.[52] This practice, along with prompt bet placement, ensures smooth progression and communal enjoyment at the table.[54]Casino-Specific Rules
In casinos, roulette tables enforce specific bet placement limits to regulate wagering and maintain game flow. Minimum bets are typically set separately for inside bets (such as straight-up numbers or splits, where the total wager must meet or exceed the table minimum) and outside bets (such as red/black or odd/even, where each individual bet must meet the minimum). For instance, a common configuration features a $1 minimum for inside bets and $5 for outside bets, though these vary by casino and table stakes. Additionally, once the dealer spins the ball and announces "no more bets," players cannot place, change, or remove wagers, ensuring fairness during the outcome determination.[55][43] The outcome of the ball landing on zero (or double zero in American wheels) triggers distinct house rules, particularly for even-money outside bets. A straight-up bet on zero pays 35:1, matching the payout for any numbered pocket. However, even-money bets lose their full amount in standard American roulette if zero appears. In contrast, many European and French roulette variants apply mitigating rules: under "la partage," half the stake on even-money bets is returned when zero lands, while "en prison" holds the full bet for the next spin—if it wins, the original stake is returned without profit; if it loses or lands on zero again, the bet is forfeited. These rules are casino-specific and often displayed on the table layout.[43] Roulette employs color-coded, non-denominated chips unique to each player to prevent confusion during betting. Upon buying in, a player receives chips in one of several colors (e.g., white, red, blue), with the value per chip set by dividing the buy-in amount by the number of chips issued—commonly stacks of 20 chips, such as $20 buy-in yielding $1 per chip.[43] Casinos limit stacks to a maximum height, often equivalent to $100 in value (e.g., 20 chips at $5 each), to ensure visibility and quick resolution by the dealer. When cashing out, these chips are exchanged only at the roulette table for value chips or currency.[43][56] Dispute resolution in roulette relies on rigorous oversight to address issues like contested bet placements or payouts. Casinos deploy surveillance cameras covering all table angles, enabling instant video review by security or pit supervisors to verify actions. In certain venues, verbal calls by players for announced bets (e.g., "voisins du zero") are considered binding if confirmed by the dealer before the spin, though physical chip placement remains the primary evidence. Unresolved disputes may escalate to gaming commission protocols, prioritizing recorded footage for impartial adjudication.[57][58]Regional Variations
Roulette exhibits significant regional differences in rules and equipment, primarily to comply with local gambling laws and traditions, affecting the house edge and gameplay. American roulette features a wheel with both a single zero (0) and double zero (00), leading to 38 pockets and a house edge of 5.26% on nearly all bets; unlike European variants, it does not incorporate the en prison rule, where even-money bets can be held over for the next spin after a zero outcome.[43][59] In contrast, European and French roulette use a single-zero wheel with 37 pockets, yielding a standard house edge of 2.70%; French roulette specifically includes the la partage rule, which applies to even-money bets (such as red/black or odd/even) when the ball lands on zero, allowing players to recover half their stake and reducing the house edge on those bets to 1.35%.[60][61][62] United Kingdom casinos typically employ single-zero wheels similar to European roulette, where call bets—verbal announcements of complex wagers like tiers du cylindre covering specific wheel sections—are commonly permitted and placed by the dealer without physical chips on the table until resolved.[63][64] In California, state laws prohibit traditional roulette wheels, so the game is adapted using a standard deck of cards (often 37 or 38 cards numbered 0 to 36 or including 00) shuffled and drawn to determine outcomes, maintaining similar odds and payouts to wheel-based versions while complying with banking and house-banked game restrictions.[65][66][67]Betting Options
Inside Bets
Inside bets in roulette refer to wagers placed directly on specific numbers or small groups of adjacent numbers on the inner section of the betting table layout. These bets offer higher potential payouts compared to outside bets due to their lower probability of winning, as they target precise outcomes on the wheel.[68][69] The primary types of inside bets include the straight-up, split, street, corner, and six-line. A straight-up bet is placed on a single number, such as 17 or 32, and pays out at 35 to 1 if the ball lands on that number.[68][69] A split bet covers two adjacent numbers, either horizontally or vertically on the table, with a payout of 17 to 1.[68][69] The street bet (or row bet) involves three consecutive numbers in a horizontal row, offering an 11 to 1 payout.[68][69] A corner bet (also known as a square bet) targets four numbers forming a square at their intersection, with an 8 to 1 payout.[68][69] Finally, the six-line bet (or double street) covers six numbers across two adjacent rows, paying 5 to 1.[68][69] To illustrate, if a player places a $1 straight-up bet on the number 17 and the ball lands on it, the player receives $35 in winnings plus the original $1 stake returned, for a total of $36.[68][69] These bets emphasize the game's focus on individual wheel pockets, requiring precise placement on the table's numbered grid.| Bet Type | Description | Payout |
|---|---|---|
| Straight-Up | Single number | 35:1 |
| Split | Two adjacent numbers | 17:1 |
| Street | Three consecutive numbers in a row | 11:1 |
| Corner | Four numbers forming a square | 8:1 |
| Six-Line | Six numbers across two rows | 5:1 |
Outside Bets
Outside bets in roulette are wagers placed on the outer areas of the betting layout, covering larger groups of numbers rather than specific ones, and offering lower risk compared to inside bets. These bets are positioned outside the main number grid on the table, typically in designated boxes or at the ends of columns, and they exclude the zero (or double zero in American roulette), meaning a spin landing on zero results in a loss for all outside bets.[43] The most common outside bets include red/black and odd/even, each covering 18 numbers on a single-zero wheel with a 1:1 payout. A red/black bet is placed on the color boxes, wagering that the ball will land on a red or black number, while odd/even bets on the respective parity boxes cover all odd or even numbers from 1 to 36.[43][70] High/low bets, also known as manque/passe in French roulette, similarly offer 1:1 payouts and cover 18 numbers each: low (1-18) or high (19-36), placed in the corresponding boxes below the even-money color and parity options. Dozen bets cover 12 numbers in groups of 1-12 (first dozen), 13-24 (second), or 25-36 (third), with 2:1 payouts, and are placed in the three dedicated dozen boxes at the bottom of the layout. Column bets, paying 2:1, wager on one of the three vertical columns of 12 numbers each (e.g., numbers ending in 1, 4, 7, etc.), with chips placed in the spaces at the base of each column.[43][71] In some UK casinos, a non-standard variant called the snake bet covers 12 red numbers in a zigzag pattern across the layout—specifically 1, 5, 9, 12, 14, 16, 19, 23, 27, 30, 32, and 34—with a 2:1 payout, requiring placement of individual chips on each number to form the "snake" shape.[72][73]Announced Bets
Announced bets, also known as call bets or spoken bets, are a feature primarily in European and French roulette variants, where players verbally announce wagers on specific sectors of the roulette wheel rather than placing chips directly on the table layout for individual numbers. These bets cover groups of numbers based on their positions on the physical wheel, allowing for broader coverage without needing to place multiple chips on the betting cloth. They originated in French casinos and are typically available only at tables with a single zero wheel, as the announcements reference the wheel's sequence.[43] The most common announced bet is Voisins du Zéro (neighbors of zero), which covers 17 numbers clustered around the zero pocket on the wheel: 22, 18, 29, 7, 28, 12, 35, 3, 26, 0, 32, 15, 19, 4, 21, 2, and 25. This bet requires nine chips in total, placed as follows: 2 chips on the 0-2-3 trio, 1 chip each on the splits 4-7, 12-15, 18-21, 19-22, and 32-35, and 2 chips on the 25-26-28-29 corner. Payouts vary by the winning bet type, such as 35:1 for straights or 17:1 for splits.[43][74] Tiers du Cylindre (third of the wheel or cylinder) targets the 12 numbers opposite the zero sector on the wheel: 27, 13, 36, 11, 30, 8, 23, 10, 5, 24, 16, and 33. This bet uses six chips, all placed as split bets: 5-8, 10-11, 13-16, 23-24, 27-30, and 33-36. If any of these numbers wins, the payout is 17:1 per chip, effectively yielding a total return based on the single winning split. This bet covers approximately one-third of the wheel's non-zero numbers, providing balanced coverage away from the zero.[43] Orphelins (orphans) refers to the eight numbers on the wheel that are not included in either Voisins du Zéro or Tiers du Cylindre: 17, 34, 6, 1, 20, 14, 31, and 9. It requires five chips: one straight-up bet on 1 and four split bets on 6-9, 14-17, 17-20, and 31-34. Payouts are 35:1 for the straight-up on 1 or 17:1 for the splits, making it a cost-effective way to cover the remaining "unpaired" wheel sections. These numbers are positioned in two small arcs, one on each side of the wheel.[43] Jeu Zéro (zero game) is a smaller announced bet focusing on the seven numbers closest to zero: 12, 35, 3, 26, 0, 32, and 15. It uses four chips: three split bets on 0-3, 12-15, and 32-35, plus one straight-up on 26. This provides high concentration around zero with lower chip requirement, paying 35:1 on 26 or 17:1 on the splits if they win. It is often used as a quick, low-stake option in French roulette.[43] Finally, Neighbors bets allow flexibility by adding adjacent numbers to a base bet, typically covering a chosen number plus two on either side (five numbers total), though variations like five or nine neighbors exist. For example, neighbors of 17 would include 2, 25, 17, 34, and 6 (based on wheel sequence), placed as five straight-up chips. Each winning number pays 35:1, and the bet size scales with the number of neighbors selected, often announced with the count (e.g., "five neighbors of 17"). This customizable approach lets players extend coverage around any wheel position.[43]Odds and Payouts
Bet Odds Table
The following table provides a comprehensive summary of standard and announced bet types in roulette, detailing the bet name, numbers covered (including count for probability calculation), payout ratio, and winning probability for the European wheel (37 pockets, single zero). Payouts for announced bets vary based on the specific sub-bet that wins, as these are combinations of inside bets. Announced bets are primarily available on European or French roulette tables. For the American wheel (38 pockets, double zero), probabilities are adjusted by dividing the covered numbers by 38 instead of 37 (e.g., straight-up bet probability decreases to approximately 2.63%), while payouts remain the same.[43][75]| Bet Name | Numbers Covered (Count) | Payout Ratio | European Probability |
|---|---|---|---|
| Outside Bets | |||
| Red or Black | 18 red or 18 black (excludes 0) | 1:1 | 48.65% |
| Odd or Even | 18 odd or 18 even (excludes 0) | 1:1 | 48.65% |
| High (19-36) or Low (1-18) | 18 high or 18 low (excludes 0) | 1:1 | 48.65% |
| Dozen (1-12, 13-24, 25-36) | 12 consecutive in a dozen (excludes 0) | 2:1 | 32.43% |
| Column | 12 in a vertical column (excludes 0) | 2:1 | 32.43% |
| Inside Bets | |||
| Straight-Up | 1 specific number | 35:1 | 2.70% |
| Split | 2 adjacent numbers | 17:1 | 5.41% |
| Street (Line) | 3 consecutive numbers in a row | 11:1 | 8.11% |
| Corner (Square) | 4 numbers forming a square | 8:1 | 10.81% |
| Six Line (Double Street) | 6 consecutive numbers across two streets | 5:1 | 16.22% |
| Announced Bets (European/French Wheels) | Varies | ||
| Voisins du Zéro | 17 numbers (0, 2-4, 7, 12, 15, 18, 19, 21, 22, 25, 26, 28, 29, 32, 35) | Varies: 35:1 (straight-up), 17:1 (split), 11:1 (street), 8:1 (corner) | 45.95% |
| Tiers du Cylindre | 12 numbers (5, 8, 10, 11, 13, 16, 23, 24, 27, 30, 33, 36) | Varies: primarily 17:1 (split) | 32.43% |
| Orphelins | 8 numbers (1, 6, 9, 14, 17, 20, 31, 34) | Varies: 35:1 (straight-up), 17:1 (split) | 21.62% |
| Jeu Zéro | 7 numbers (0, 3, 12, 15, 26, 32, 35) | Varies: 35:1 (straight-up), 17:1 (split) | 18.92% |
| Neighbors (5) | 5 consecutive numbers around a chosen one | 35:1 (straight-up) | 13.51% |
House Edge Calculation
The house edge in roulette represents the casino's average profit margin per unit wagered, derived from the expected value (EV) of each bet. The EV for a bet is calculated as EV = \sum (p_i \cdot o_i), where p_i is the probability of each outcome and o_i is the corresponding payout (positive for wins, negative for losses). The house edge is then HE = -EV \times 100\% for a unit bet.[43][1] In European roulette, with 37 pockets (numbers 1-36 and a single 0), the house edge is uniform at approximately 2.70% for most bets, including even-money wagers like red/black or odd/even. For an even-money bet, the probability of winning is \frac{18}{37}, yielding a payout of 1:1 (net +1 unit), while the probability of losing is \frac{19}{37} (-1 unit). Thus, EV = \left( \frac{18}{37} \cdot 1 \right) + \left( \frac{19}{37} \cdot (-1) \right) = -\frac{1}{37} \approx -0.027, so HE = \frac{1}{37} \approx 2.70\%. This can also be expressed as HE = \left(1 - \left(1 \cdot \frac{18}{37}\right)\right) \times 100\% = \frac{19}{37} \times 100\% \approx 2.70\%, though the EV approach generalizes to all bet types.[43][1] American roulette introduces a double zero (00), expanding the wheel to 38 pockets and doubling the house edge to 5.26% for most bets. For even-money bets, the win probability drops to \frac{18}{38}, with loss probability \frac{20}{38}. The EV is \left( \frac{18}{38} \cdot 1 \right) + \left( \frac{20}{38} \cdot (-1) \right) = -\frac{2}{38} = -\frac{1}{19} \approx -0.0526, yielding HE = \frac{2}{38} \approx 5.26\%. Exceptions include the five-number bet (0, 00, 1, 2, 3), which has a higher edge of 7.89% due to its payout structure not fully compensating for the five favorable outcomes out of 38.[43][1] The French roulette variant mitigates the house edge on even-money bets through the la partage rule, which returns half the wager if the ball lands on 0. Under this rule, the EV becomes \left( \frac{18}{37} \cdot 1 \right) + \left( \frac{18}{37} \cdot (-1) \right) + \left( \frac{1}{37} \cdot (-0.5) \right) = -\frac{0.5}{37} \approx -0.0135, reducing the house edge to 1.35%. This applies only to even-money outside bets and does not affect other wagers, which retain the standard 2.70% edge.[43] Announced bets, such as voisins du zéro or tier, are combinations of underlying straight-up or split bets and thus inherit the same house edge as their components—2.70% in European/French roulette (or 5.26% in American, where applicable). For example, voisins du zéro covers nine numbers with varying units but maintains the overall edge through balanced probabilities and payouts equivalent to individual straight-up bets (35:1 payout, \frac{1}{37} probability each).[43]Payout Structures
In roulette, payouts follow standardized ratios based on the bet type, ensuring consistent returns across casinos. A straight-up bet on a single number pays 35 to 1, returning the stake plus 35 times the wager amount if that number wins. Even-money outside bets, such as those on red or black, odd or even, or high or low, pay 1 to 1, doubling the stake for a win. These ratios apply universally in both European (single-zero) and American (double-zero) wheels, with the full payout including the original bet.[76][43] In physical casinos, winnings are distributed in colored chips unique to each player, where the value per chip is determined by dividing the buy-in by 20, forming standard stacks of 20 chips for efficient handling and payout. When multiple bets placed by a player win on the same outcome, each is settled independently without overlap penalties; for instance, a straight-up bet on the winning number pays 35 to 1, while a concurrent split bet covering that number and another pays 17 to 1 separately, allowing full returns on all valid wagers. This independent calculation prevents double-dipping by treating each chip placement as a distinct bet.[77][43] Outcomes involving the zero pocket alter payouts significantly: a straight-up bet on zero pays the standard 35 to 1, but all outside bets lose in full on zero (or double zero), except in variants with rules like en prison, where even-money bets may retain half the stake. This structure maintains the game's integrity by enforcing losses on non-winning categories.[43] Online roulette platforms deliver payouts as instant digital credits added to the player's account balance immediately after each spin, streamlining the process without physical handling. Certain online variants feature progressive jackpots, where a small deduction from qualifying bets accumulates into a shared prize pool that triggers additional large wins beyond standard ratios, often randomly or on specific outcomes.[76][78]Mathematical Foundations
Probability Model
The probability model for roulette assumes a fair wheel where the ball is equally likely to land in any pocket, establishing a uniform discrete probability distribution over the outcomes. In the European variant, which features 37 pockets numbered from 0 to 36, each individual pocket has a probability of exactly \frac{1}{37} \approx 0.0270.[79] This uniformity implies that the probability of the ball landing on any specific number is identical across all spins under ideal conditions.[80] Combinatorial probabilities arise when considering bets that cover multiple pockets, such as colors or parity. For instance, there are 18 red pockets out of 37, yielding a probability of red on a single spin of \frac{18}{37} \approx 0.4865; similarly, the probability of black or even is also \frac{18}{37}, while the single green zero pocket accounts for the remaining \frac{1}{37}.[80] These probabilities reflect the fixed composition of the wheel, where outcomes are partitioned into mutually exclusive and exhaustive events.[79] A core assumption of the model is the independence of spins: the result of one spin does not influence subsequent spins, as the wheel resets to a random starting position each time.[80] This lack of memory ensures that probabilities remain constant across trials.[79] For analyzing sequences of spins, particularly even-money bets like red or black, the number of successful outcomes in n independent spins follows a binomial distribution. Here, each trial has success probability p = \frac{18}{37}, and the probability of exactly k successes is given by the binomial probability mass function: P(K = k) = \binom{n}{k} p^k (1-p)^{n-k} for k = 0, 1, \dots, n. This model captures the variability in outcomes over multiple plays, such as the likelihood of breaking even or profiting in a fixed number of spins.[81]Expected Value Analysis
The expected value (EV) in roulette represents the average amount a player can expect to win or lose per unit bet over many repeated plays, assuming fair randomness and standard rules. It is calculated as the sum of each possible outcome multiplied by its probability:\text{EV} = p_{\text{win}} \cdot (\text{payout}) + p_{\text{loss}} \cdot (-1),
where p_{\text{win}} is the probability of winning, the payout is the net profit on a winning bet (excluding the stake), and losses result in forfeiting the stake.[82] This metric quantifies the game's inherent disadvantage for the player, as the EV is negative across all bets due to the house's edge from the zero(s) on the wheel.[83] For a straight-up bet on a single number in European roulette (37 pockets), the probability of winning is \frac{1}{37}, with a payout of 35 units, and the loss probability is \frac{36}{37}. Thus,
\text{EV} = \left( \frac{1}{37} \right) \cdot 35 + \left( \frac{36}{37} \right) \cdot (-1) = -\frac{1}{37} \approx -0.027,
meaning the player loses about 2.7 cents per dollar bet on average.[82] In contrast, even-money bets (e.g., red/black) in European roulette also yield \text{EV} = -\frac{1}{37} \approx -0.027, as the win probability is \frac{18}{37} with a 1-unit payout, and loss probability \frac{19}{37}.[82] For American roulette (38 pockets), even-money bets have a lower EV of -\frac{2}{38} = -\frac{1}{19} \approx -0.0526, due to the additional double zero increasing loss chances to \frac{20}{38}.[83] Variance measures the spread of outcomes around the EV, highlighting the risk in different bets. Inside bets like straight-up exhibit high variance; for a unit straight-up bet in European roulette, the variance is approximately 34.08 (or roughly 35 when approximating), reflecting the large potential swings from rare big wins against frequent small losses.[83] Even-money bets have much lower variance, around 0.99, as outcomes are closer to the mean with smaller payouts.[83] By the law of large numbers, as the number of independent bets increases, the average return per bet converges to the EV, ensuring long-run losses approach the proportional house advantage regardless of short-term fluctuations.[84] This principle underscores why no betting strategy can overcome the negative EV in the aggregate, though variance influences the path to convergence.[85]
Wheel Bias and Physics
Wheel bias in roulette arises from physical imperfections in the wheel that deviate from ideal uniformity, leading to non-random outcomes favoring certain numbers or sectors. Common causes include wear and tear on the frets (the metal dividers between pockets) and pockets themselves, which can loosen or deform over time, causing the ball to settle more frequently in affected areas. Tilt imperfections, such as a slight slant in the wheel's base or table surface, also contribute significantly by directing the ball toward lower sectors due to gravitational pull.[86][87] A seminal historical exploitation of wheel bias occurred in 1873 at the Monte Carlo casino, where British engineer Joseph Jagger identified and profited from such flaws. Jagger employed clerks to record thousands of spins across the casino's six wheels, detecting one biased toward nine specific numbers due to manufacturing defects. Over three days, he won the equivalent of approximately £3 million (in modern terms), famously "breaking the bank" multiple times and demonstrating the vulnerability of imperfect wheels to systematic observation.[88] The physics underlying roulette outcomes involves the ball's trajectory as it decelerates along the wheel's track before entering the rotating pockets. Ball velocity decays primarily due to friction with the track and air resistance, causing it to spiral inward over 15–20 revolutions before dropping; this process is modeled deterministically but becomes sensitive to initial conditions. The Coriolis effect, arising from Earth's rotation, is negligible in roulette due to the small scale and low velocities involved, exerting forces orders of magnitude smaller than friction or gravity. Chaos theory further limits practical prediction, as minute variations in initial ball speed, wheel tilt, or pocket dimensions amplify unpredictably through the ball's bounces off deflectors, rendering long-term forecasting infeasible without precise, real-time measurements.[86][89] Casinos employ modern countermeasures to mitigate bias, including frequent calibration and maintenance to ensure level surfaces and uniform pockets. Wheels are routinely inspected, leveled with precision tools, and replaced if defects exceed tolerances, often after 10,000–20,000 hours of use. In electronic or automated roulette variants, air jets propel the ball along the track to introduce additional randomization, reducing predictability from mechanical flaws.[90][91] Bias detection relies on statistical analysis of spin outcomes, particularly the chi-squared goodness-of-fit test, which compares observed number frequencies against expected uniform probabilities (1/37 for European wheels). Reliable detection requires observing over 5,000 spins to achieve sufficient statistical power, as smaller samples are prone to random variance; for instance, a chi-squared value exceeding critical thresholds (e.g., >51.0 at 95% confidence for 36 degrees of freedom) indicates significant deviation. Such tests have been applied in academic studies to validate biases in real wheels, confirming their presence only with large datasets.[87][92]Strategies and Systems
Common Betting Systems
Common betting systems in roulette are structured approaches to wagering, primarily applied to even-money outside bets such as red/black, odd/even, or high/low, which offer nearly 50% winning chances. These strategies, often progressive in nature, adjust bet sizes based on outcomes to manage risk and pursue consistent small gains, though they cannot overcome the game's house edge. Popular examples include the Martingale, Reverse Martingale (Paroli), Labouchère, D'Alembert, and Fibonacci systems, each with distinct progression rules designed for session-long play. Martingale SystemThe Martingale system, which emerged in 18th-century France and gained prominence among European gamblers, operates as a negative progression strategy. Players begin with a base bet on an even-money outcome and double the wager after every loss, resetting to the initial amount after a win. This method ensures that a single win recovers all prior losses plus a profit matching the original stake, assuming unlimited funds and no table limits. In practice, casinos impose maximum bet caps, often around 100 times the minimum, which can halt the progression during extended losing streaks.[93] Reverse Martingale (Paroli) System
The Reverse Martingale, commonly known as the Paroli system, flips the Martingale's logic into a positive progression approach, encouraging players to exploit winning streaks. Starting with a base bet on an even-money option, the player doubles the stake after each win, typically for up to three consecutive successes, then pockets the winnings and returns to the base bet regardless of the next outcome. This conservative tactic limits exposure during losses by maintaining the initial bet size after defeats, focusing gains on short hot runs while preserving bankroll.[94] Labouchère System
The Labouchère system, also called the cancellation or split-Martingale, involves creating a line of numbers that sum to the player's target profit, such as writing "1-2-3-4" for a ten-unit goal. The bet equals the sum of the first and last numbers in the line (e.g., 1+4=5 units) placed on an even-money bet; a win crosses off those numbers, while a loss adds the bet amount to the line's end. Play continues until the line is cleared, achieving the profit, or the bankroll depletes; this methodical progression allows customization of risk through sequence length.[95] D'Alembert System
Named after 18th-century French mathematician Jean le Rond d'Alembert, this system uses a mild negative progression suited to even-money roulette bets. Players select a unit size and start betting that amount, increasing by one unit after a loss and decreasing by one unit after a win, with ties prompting repetition of the current bet. The strategy assumes outcomes will even out over time, enabling steady recovery of losses through incremental adjustments rather than aggressive escalation.[96] Fibonacci System
The Fibonacci system draws from the mathematical sequence defined by Leonardo of Pisa (Fibonacci) in the 13th century—where each number is the sum of the two preceding ones (1, 1, 2, 3, 5, 8, etc.)—adapted for betting. Players bet the next sequence number after a loss on an even-money wager and move back two positions after a win, starting and often resetting to the first 1 upon success. This graduated progression recovers multiple losses upon a win while advancing more slowly than doubling systems, requiring a sequence list for tracking.[97]