Numbeo
Numbeo is a crowd-sourced online database aggregating user-submitted numerical data on consumer prices, property values, and quality-of-life metrics for cities and countries worldwide, enabling comparisons of living costs and conditions.[1][2]
Founded in 2009 by Mladen Adamović, a former Google software engineer, the platform operates as a for-profit entity with the goal of providing accessible, user-contributed information to inform personal and business decisions on relocation and expenses.[3][4]
Key features include the Cost of Living Index, which benchmarks average family expenses against New York City as 100, derived from reported prices for groceries, housing, transportation, and utilities; the Quality of Life Index, factoring in purchasing power, pollution, healthcare, traffic, and housing affordability; and the Crime Index, based on perceived safety levels rather than official records.[5][6][7]
Data collection relies on voluntary contributions from users, weighted by recency and contribution volume, which allows broad coverage but introduces variability in accuracy and potential subjective biases, particularly for perception-based metrics like crime that often differ from government statistics.[2][7][8]
Numbeo has grown into one of the largest such repositories, frequently referenced for global rankings, though its crowd-sourced nature prioritizes user experiences over verified empirical controls.[9][10]
History
Founding and Initial Launch
Numbeo was founded in April 2009 by Mladen Adamović, a former software engineer at Google, with the aim of creating a crowd-sourced platform for comparing consumer prices and living costs across cities and countries.[2][4][8] Prior to its launch, no free, publicly accessible online database existed that allowed individuals to easily estimate and compare personal expenses based on real-time user-submitted data, addressing a gap in available tools for relocation decisions and economic analysis.[2] The platform emphasized independence, with data collection and research explicitly uninfluenced by governmental organizations.[3] Initially, Numbeo operated as a for-profit entity under Numbeo doo, a company registered in Serbia, with headquarters in Belgrade at Dvadesetsedmog Marta 20/35.[4][11] The site's core mechanism relied on voluntary contributions from users worldwide, who submitted prices for everyday goods, services, and housing to build a dynamic database.[3] This user-driven approach enabled rapid aggregation of information without reliance on official statistics, focusing on practical, verifiable inputs like supermarket prices and utility costs to facilitate cross-location comparisons.[2] By prioritizing empirical, crowdsourced data over institutional sources, the platform sought to provide unbiased insights into economic conditions.[12]Expansion and Key Milestones
Following its launch in April 2009, Numbeo expanded its scope from basic consumer price comparisons to a broader array of living condition metrics, driven by increasing user contributions that enabled data aggregation across growing numbers of cities worldwide. The platform incorporated manual data from official sources like supermarkets and government statistics, weighted higher than crowd-sourced inputs to enhance reliability, with updates occurring twice annually. This growth in data volume supported the development of foundational indices, such as the Cost of Living Index and Local Purchasing Power Index, which use weighted baskets of goods and services for a four-person family as benchmarks.[2] By the mid-2010s, Numbeo had introduced additional composite indices, including the Quality of Life Index, which empirically combines purchasing power, safety, health care quality, cost of living, property prices, traffic commute times, and pollution levels to rank urban areas. This expansion reflected the platform's adaptation to user demand for holistic assessments, with data filters and adaptive archiving methods—such as retaining recent contributions from high-contributor cities for three months—implemented to maintain accuracy amid rising submissions. Coverage extended to hundreds of cities, facilitating tools like historical data explorers for trend analysis.[13][2] Key milestones include reaching comprehensive global coverage by the early 2020s, with over 578 cities benchmarked for cost-of-living comparisons by 2022, and the establishment of semi-annual index publications, such as the 2025 mid-year rankings, which continue to incorporate real-time currency adjustments and expanded metrics like traffic and crime indices. Numbeo's reliance on crowd-sourcing has sustained organic growth without formal partnerships, though its data has been referenced in economic analyses for cross-city evaluations.[14][15]Methodology
Data Collection Process
Numbeo's data collection relies primarily on crowd-sourced contributions from registered users who submit prices, survey responses, and other metrics via the website's input forms. Users provide details such as local prices for goods and services (e.g., milk, gasoline, rent), perceptions of crime levels, safety, pollution, and quality-of-life factors through structured surveys scaled from -2 to +2 or similar ranges, which are then normalized to 0-100 scales.[2][7][6] This user-generated data forms the bulk of the database, with submissions archived for typically 12 months, adjustable to 3 months in high-contributor cities or up to 18 months in low-inflation environments to balance recency and volume.[2] To supplement crowd-sourced inputs, Numbeo operators manually gather data biannually from authoritative external sources, including supermarket websites, taxi company tariffs, and governmental reports, assigning these entries three times the weight of user submissions to enhance reliability.[2] For price data, contributions are filtered by item-specific relevance (e.g., higher weights for staples like milk at 25 versus gasoline at 60 in index calculations), while crime and quality-of-life surveys require a minimum threshold of contributors per city for statistical validity, drawing from visitor perceptions structured akin to formal surveys.[2][7][6] Quality assurance involves over 30 automated and semi-automated filters to detect and mitigate spam, noise, and outliers, analyzing user behavior, IP addresses (e.g., excluding public proxies and Tor nodes), historical patterns, and statistical anomalies. Heuristic algorithms further excise improbable entries against benchmarks, with misclassified data potentially reintegrated if it proves statistically sound; country-level aggregates are weighted by contributor volume.[2] Currency exchange rates update near-hourly from external feeds, ensuring timeliness, though the crowd-sourced model's dependence on voluntary inputs can introduce variability absent in fully curated datasets.[2]Index Calculation and Formulas
Numbeo's indices are calculated using aggregated crowd-sourced data from user contributions, supplemented by manually verified inputs from sources such as supermarkets and government statistics, with manual data weighted three times higher than user-submitted data to enhance reliability.[2] All indices are relative to New York City, set as the base with an index value of 100, allowing comparisons of relative costs, qualities, or risks across locations.[2] Data aggregation employs filters to exclude outliers and spam, with country-level indices weighted by the number of contributors per city rather than simple averages.[2] The Cost of Living Index (excluding rent) is derived by summing the products of individual item prices and predefined cost-of-living factors, then scaling relative to New York City's equivalent value and multiplying by 100.[2] Specific weights include higher values for essentials like milk (factor of 25) compared to utilities (e.g., basic electricity at 8), reflecting their proportional impact on household budgets.[2] The formula is:(Σ (price × cost_of_living_factor) / New York City value) × 100.[2] Sub-indices such as Groceries Index and Restaurants Index follow similar weighted averaging of relevant categories, benchmarked against New York City.[5]
The Rent Index applies a parallel approach, using rent-specific factors (e.g., 0.25 for one-bedroom apartments in city centers) to weight rental prices before scaling to the New York City baseline.[2] The Cost of Living Plus Rent Index combines the two by summing their weighted components.[2] The Local Purchasing Power Index measures affordability by comparing net average monthly salaries against the cost of a standard consumption basket (for a four-person family, including rent) relative to New York City:(City net salary / City basket cost) / ([New York City](/page/New_York_City) net salary / [New York City](/page/New_York_City) basket cost) × 100.[2]
The Quality of Life Index employs an empirical formula aggregating multiple sub-indices with assigned weights to estimate overall livability, where higher values indicate better conditions.[6] It incorporates: Purchasing Power Index (divided by 2.5), Safety Index (divided by 2.0), Health Care Index (divided by 2.5), Climate Index (divided by 3.0), minus penalties for House Price to Income Ratio (×1.0), Cost of Living Index (/10), Traffic Commute Time Index (/2.0), and Pollution Index (×2/3).[6] The formula, updated post-December 2017, is:max(0, 100 + (PurchasingPower/2.5) - (HousePriceToIncome×1.0) - (CostOfLiving/10) + (Safety/2.0) + (Health/2.5) - (TrafficTime/2.0) - (Pollution×2/3) + (Climate/3.0)).[6] Weights are adjusted periodically based on empirical refinements.[6]
For crime-related metrics, the Crime Index processes user perceptions from surveys rating factors on a -2 to +2 scale, including level of crime (weighted ×3), worries about theft or assault, and corruption prevalence across 15 categories.[7] The summed and averaged score is scaled to 0-100, with an additional adjustment for high values: (Average / 2) + (if Average > 20, (Average - 20)^1.65).[7] The Safety Index inverts this by negating crime-level inputs before similar aggregation and scaling.[7] Formulas for both evolve via complex empirical models to better reflect reported perceptions.[7]
Quality Assurance Measures
Numbeo employs over 30 sophisticated automatic and semi-automatic filters to maintain data accuracy and integrity, with filter efficacy improving as more user inputs accumulate.[2] These filters leverage heuristic technology to detect and remove statistically improbable or incorrect submissions, drawing on benchmarks from historical data and user behavior patterns.[2] Spam detection includes IP-based restrictions, such as blocking inputs from public proxies and Tor nodes, alongside algorithms that identify suspicious user patterns, as applied in indices like pollution surveys.[2][16] To further validate contributions, Numbeo weights manually entered data—sourced from supermarkets and government reports—three times higher than crowd-sourced inputs to prioritize reliability.[2] Discarded data undergoes periodic re-evaluation; if it aligns statistically with accepted inputs (e.g., low standard deviation among non-spam entries), it may be reinstated, while misclassified spam is corrected accordingly.[2] Data freshness is enforced by archiving entries older than 12 months, reduced to 3 months in high-volume cities, with extensions up to 18 months possible during periods of stable inflation to avoid unnecessary loss.[2] These measures aim to mitigate biases inherent in crowd-sourcing, though specifics of the proprietary heuristics remain undisclosed, limiting independent verification of their robustness.[2]Core Features and Indices
Cost of Living Index
Numbeo's Cost of Living Index measures the relative prices of consumer goods and services, excluding rent, across cities worldwide, with New York City serving as the baseline at 100.[5] An index value above 100 indicates higher costs than New York City, while a value below signifies lower costs; for example, a score of 80 reflects expenses approximately 20% cheaper.[5] This index draws from crowdsourced user submissions, aggregating millions of price points to estimate average monthly outlays for essentials, primarily calibrated for a four-person family.[2] The index encompasses key expenditure categories such as groceries (e.g., milk, bread, rice, fruits, vegetables, alcohol), restaurant meals (e.g., inexpensive lunches, mid-range dinners for two, fast food), transportation (e.g., public transit tickets, taxi fares, gasoline, vehicle purchases), utilities (e.g., electricity, heating, water, internet, mobile plans), clothing and footwear (e.g., jeans, dresses, sneakers), and sports/leisure (e.g., gym memberships, cinema tickets).[2] Property prices per square meter in city centers and suburbs are sometimes factored in for broader context, though rent is excluded from the core index.[2] Calculation involves multiplying reported prices by predefined weights that reflect each item's proportional impact on total expenses—such as a weight of 25 for milk or 60 for gasoline—then summing these values and normalizing against New York City's weighted total, multiplied by 100.[2] Weights are periodically adjusted based on empirical consumption patterns to maintain relevance.[2] A related Cost of Living Plus Rent Index extends this by incorporating rental costs via summed factors for living expenses and rent, similarly benchmarked to New York City.[2] These indices support tools like city comparisons and relocation calculators, updated in real-time as new data accumulates from over 864,000 contributors across more than 12,500 cities as of mid-2025.[17]Quality of Life Index
The Quality of Life Index provided by Numbeo estimates the overall quality of life in cities and countries through a composite measure derived from user-contributed data and perceptions.[6] It incorporates multiple sub-indices reflecting economic, environmental, health, and safety factors, with higher values indicating better perceived living conditions.[6] The index supports comparisons across locations, aiding users in relocation, travel, or investment decisions by aggregating crowd-sourced inputs filtered for reliability.[10] Key components include the Purchasing Power Index (adjusted for rent), Safety Index, Health Care Index, Cost of Living Index, House Price to Income Ratio, Traffic Commute Time Index, Pollution Index, and Climate Index.[6] These draw from surveys on factors such as affordability, crime rates, medical access, commute durations, air quality, and weather suitability.[10] Data collection relies on voluntary user submissions, combined with manual verifications from official sources where available, and applies filters to exclude outliers or insufficient responses.[2] The index is computed via an empirical formula that weights sub-indices according to their estimated impact on livability:index.main = Math.max(0, 100 + purchasingPowerInclRentIndex / 2.5 - housePriceToIncomeRatio * 1.0 - costOfLivingIndex / 10 + safetyIndex / 2.0 + healthIndex / 2.5 - trafficTimeIndex / 2.0 - pollutionIndex * 2.0 / 3.0 + climateIndex / 3.0).[6] This structure emphasizes positive contributors like safety and purchasing power while penalizing negatives such as pollution and housing costs, with the baseline normalized around 100. Weights have evolved, with a prior revision implemented before December 2017 to refine factor importance.[6] Indices are updated continuously as new data accumulates, enabling real-time rankings, such as mid-2025 assessments showing top performers in Western Europe and Oceania.[15]