Population and demographic figures “by ZIP code” come from the U.S. Census Bureau, which publishes them for ZIP Code Tabulation Areas, or ZCTAs. ZCTAs are statistical areas built from census blocks to approximate ZIP codes; they are the standard source, but they are not the same thing as postal ZIP codes.
ZIP codes versus ZCTAs
A postal ZIP code is a set of delivery routes and can change whenever USPS reorganizes delivery. A ZCTA is a fixed area drawn once per decennial census from the most common ZIP of the addresses in each block. Most ZCTAs match their ZIP closely, but PO Box-only and unique ZIP codes have no ZCTA at all, and boundaries can differ at the edges. The Census Bureau's Census ZCTA guidance explains the method.
Where to find the numbers
- Open data.census.gov.
- Search for a table such as “DP05” (demographic profile) or “S1901” (income).
- Filter geography to ZIP Code Tabulation Area and pick the five-digit ZCTA.
The American Community Survey five-year estimates are the usual source for ZCTA-level data because one-year estimates are not published for small areas.
Read the estimates correctly
ACS figures are survey estimates with margins of error, and for small ZCTAs those margins can be wide. Always record the dataset, table, vintage year and margin of error next to any figure you publish, and compare ZCTAs only within the same vintage.
What this site provides
Every ZIP page here now shows Census Bureau figures for the matching ZCTA, when one exists: land area from the Census Gazetteer file, and population, median household income, median home value and housing units from the American Community Survey 5-Year Estimates. Figures are shown exactly as Census publishes them, with the source and vintage stated on the page. Unique, PO Box-only and some territorial ZIP codes have no matching ZCTA and show no figures rather than an estimate. For the same numbers with more geographies and tables, or a different vintage, start from the ZIP code lookup to find the ZIP's page, or look up the same five digits directly on data.census.gov.