Methodology
Last updated: 2026 · Data vintage: 2023 ACS 5-Year Estimates
Overview
CostOfLivingData.com aggregates data from six authoritative government and research sources to provide comprehensive, unbiased cost of living information for 32,000+ US cities and census-designated places (CDPs). All data is fetched programmatically, cleaned, and merged via an automated Python pipeline.
Data Sources
US Census Bureau — American Community Survey (ACS) 5-Year Estimates
Vintage: 2023 · Geography: City/Place level
The backbone of our dataset. We pull 44 variables from the Census API covering: income, housing costs, tenure, employment, commute times and modes, education, age, and poverty. The 5-year ACS provides stable estimates for small geographies that annual surveys cannot reliably cover.
Sentinel values: Census uses -666,666,666 to indicate missing or suppressed data. We treat all negative values as null.
Bureau of Labor Statistics — Average Price Data (APU series)
Vintage: 2023 annual average · Geography: National
We pull 7 commodity price series: eggs (dozen), white bread (lb), milk (gallon), ground beef (lb), electricity (kWh), utility natural gas (therm), and gasoline (gallon). These are national averages — local prices vary but are not available at city level from BLS.
Zillow Research Data — ZHVI & ZORI
Vintage: Most recent monthly value · Geography: City
Zillow Home Value Index (ZHVI) for single-family residences and condos (middle tier, seasonally adjusted). Zillow Observed Rent Index (ZORI) for all homes including multifamily. We use city-level files and match to Census places via fuzzy name matching (rapidfuzz, 85% threshold, same-state only).
NOAA — 1991–2020 Climate Normals
Vintage: 30-year normals 1991–2020 · Geography: Weather station
Monthly normal temperatures (high/low in °F) and precipitation/snowfall (inches) from NOAA's NWS first-order station network (USW* stations). Each city is matched to the nearest station by haversine distance using Census Gazetteer lat/lon coordinates. Non-USW stations (COOP sites) are excluded because they only report precipitation, not temperature.
HUD — Fair Market Rents (FY2025)
Vintage: FY2025 · Geography: County/HMFA
HUD publishes Fair Market Rents (FMRs) annually for studio through 4-bedroom units at the county level. We join these to cities using state FIPS codes. Where a direct place-to-county mapping is unavailable, we use state-level median FMRs as a fallback. FMRs represent the 40th percentile of gross rents for standard quality units.
Tax Foundation — State Tax Rates
Vintage: 2024–2025 · Geography: State
State income tax top marginal rates (or flat rates where applicable), state sales tax rates, average local sales tax add-ons, and effective property tax rates as published by the Tax Foundation. These are state-level figures applied uniformly to all cities within a state.
Cost Index Calculation
The "Cost Index" displayed on city pages is a simplified housing-weighted composite:
Where each sub-index is the city value divided by the national median, multiplied by 100. A score of 100 = exactly at national average. Under 90 = notably below average (green). Over 110 = notably above average (red).
Limitations
- Census ACS 5-year estimates have margins of error, especially for small populations.
- BLS grocery and energy prices are national averages; they do not reflect local variation.
- NOAA climate data uses the nearest weather station, which may be 20–50 miles from smaller cities.
- HUD FMR data uses state-level medians for most cities due to the lack of a complete place-to-county crosswalk.
- Zillow data is only available for ~21,000 of the 32,000+ Census places.
- Tax rates are state-level; local income and sales taxes are not captured.
Update Frequency
The pipeline is designed to be re-run annually when new Census ACS 5-year estimates are released (typically December of each year). The data pipeline is written in Python and all source data is downloaded from official APIs and public data repositories.