Methodology | City Zip Compare

Source dataset

Unless otherwise noted, every metric uses the U.S. Census Bureau's American Community Survey 5-year estimates (ACS5), most recent vintage available via the Census Data API. ACS5 aggregates roughly 60 months of household responses, which gives stable, publishable estimates even for small geographies (small ZCTAs, low-population counties).

Geographies

ZIP code: we use Census ZCTAs (ZIP Code Tabulation Areas), which are the closest tabulated approximation to USPS ZIPs. ZCTAs match USPS ZIPs in most cases; differences are typically a handful of households on the boundary.
City: Census Designated Place (CDP) or incorporated place, identified by state FIPS + place FIPS.
County: identified by state FIPS + county FIPS.
State: 50 states plus the District of Columbia.

Metric definitions

Population — B01003

Total population estimate for the geography.

Median age — B01002

Median age of all residents.

Median household income — B19013

Median pre-tax income for occupied households, including wages, self-employment, retirement, investment income, and public assistance. Reported in current-year inflation-adjusted dollars.

Median home value — B25077

Owner-estimated market value of owner-occupied housing units. This is a stated estimate, not a transaction price; it tends to lag market peaks and troughs by 6–18 months.

Median gross rent — B25064

Contract rent plus the estimated average monthly cost of utilities and fuels paid by the renter. This is what tenants actually pay out of pocket each month, not "asking rent" on listing sites.

Homeownership rate — B25003

Owner-occupied units (B25003_002E) divided by total occupied units (B25003_001E), as a percentage.

Unemployment rate — B23025

Civilian unemployed (B23025_005E) divided by civilian labor force (B23025_003E). Note this is the ACS five-year smoothed rate, not the monthly Bureau of Labor Statistics headline figure.

Educational attainment — B15003

Universe is residents 25 years and older. "Bachelor's or higher" sums variables _022E through _025E (bachelor's, master's, professional, doctorate). "High school or higher" sums _017E through _025E.

Average commute — B08013 / B08303

Aggregate travel time to work (B08013_001E) divided by total commuters (B08303_001E). Reported in minutes, one-way.

Comparative phrasing

When we say a value is "above" or "below" the U.S. median, we use the most recent ACS5 national release as the benchmark. The five descriptive bands are:

Well below: more than 20% under the U.S. median
Below: 5–20% under
Near: within ±5%
Above: 5–20% over
Well above: more than 20% over

Rounding and missing values

Rates are rounded to one decimal place. Dollar values are reported as Census publishes them (whole dollars). Where Census suppresses a value (small sample, the sentinel value −666666666, or N/A for the geography), we display "—" rather than guessing.

Known limitations

ZCTAs are not USPS ZIPs. Small differences exist on boundaries and for PO-box-only ZIPs.
ACS5 is a moving five-year average. It will lag rapid changes (post-pandemic migration, sudden housing booms) by 1–3 years.
Median home value reflects owner self-estimates, not market transactions.
Unemployment is the ACS smoothed rate; BLS monthly figures are more current for short-term labor-market analysis.