Where our data comes from

Every figure published on a ZIP code profile is drawn from one of two authoritative, publicly documented sources:

• U.S. Census Bureau — American Community Survey (ACS) 5-year estimates, 2018–2022. Population, age, household income, per-capita income, poverty rate, and housing characteristics (home values, rents, occupancy, ownership) are ACS estimates published at the ZIP Code Tabulation Area (ZCTA) level.
• Zillow Home Value Index (ZHVI). Where available, we show Zillow’s monthly smoothed, seasonally adjusted typical home value for a ZIP code, labeled with the month it reflects.

What a ZIP code is here

ZIP codes are USPS mail-delivery routes, not statistical areas. The Census Bureau publishes data for ZIP Code Tabulation Areas (ZCTAs), which approximate ZIP codes but are not identical. When we say “ZIP code” on a data page, the underlying demographic and housing figures are ZCTA estimates.

Our quality gate

Not every ZIP code in our raw dataset has data we are willing to publish. Before a profile is indexed, listed in a sitemap, or shown ads, it must pass an automated quality gate. A profile is excluded when it:

• matches a known placeholder/synthetic fingerprint (data that was generated rather than sourced);
• has zero or missing population;
• falls below a minimum population floor (very small ZCTAs where estimates are unreliable); or
• is missing required city/state or core demographic or housing records.

Excluded ZIP codes still resolve to a page, but that page is marked noindex, shows a clear “limited data” notice, and carries no advertising. Of roughly 42,700 ZIP codes in the raw dataset, approximately 31,000 currently pass the gate and are published.

What we deliberately do not publish

We only publish fields we can trace to a cited source. We do not publish crime or safety scores, school ratings, weather, or composite “livability” indexes, because we do not have a verifiable, real source for them. Where such fields once appeared, they have been removed rather than estimated.

Comparisons and context

Comparative statements (for example, how a ZIP’s median income or home value compares to its state) are computed directly from the same sourced fields and are meant as decision-useful context, not as rankings or advice.

Corrections

If you believe a figure is wrong, tell us. See our corrections policy for how we handle reports and updates. For the full list of sources and their limitations, see Data Sources.