Methodology

1. Geography: ZIP codes vs. ZCTAs

A ZIP code is a USPS delivery route, not a geographic area, and the Census Bureau does not publish statistics for it directly. Every demographic figure on this site is reported for the corresponding ZIP Code Tabulation Area (ZCTA), the Census Bureau's approximation of a ZIP code built from whole census blocks. For most residential Denver ZIPs the two match closely. Five of the 44 ZIPs we list (80217, 80264, 80290, 80293, 80294) are PO Box ZIPs with no resident population, and 80208 is the University of Denver campus ZIP with no ACS estimate; their pages say so and they are excluded from rankings and reports. County assignments (Denver, Adams, Arapahoe, Jefferson) are the site's own for ZIPs that straddle the city line. Place names, coordinates and ZIP types come from USPS designations via the Zippopotam.us open ZIP API and Census TIGER/Line files.

2. Primary source: ACS 2020–2024 5-Year Estimates

Population, median age, median household income, median home value (owner-occupied units), housing units, owner and renter shares, high-school and bachelor's attainment (population 25 and over), unemployment and mean travel time to work come from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates, retrieved in March 2026 from data.census.gov and Census Reporter at the ZCTA level: tables B01003, B01002, B19013, B25077, B25003, B25001, B15003, B23025 and B08303. The 5-year product is used because 1-year estimates are only published for geographies of 65,000 or more people, which excludes almost every ZIP code. A 5-year estimate describes the average condition across the whole 2020–2024 window rather than a single point in time; a ZIP that changed quickly in 2023–2024 (RiNo, Five Points, Sloan's Lake) will read as slightly older than it is. Median gross rent is not currently in the dataset.

3. Figures we compute ourselves

• Price-to-income ratio = median home value ÷ median household income. 3.0 is the long-run U.S. norm for a home the local median earner can finance conventionally; ratios above 5.0 are conventionally described as severely unaffordable.
• Metro benchmarks ("above the Denver average") are computed across the ZIPs with ACS figures, each ZIP weighted equally, not by population. Population-weighted figures would sit closer to Denver County's values.
• Rankings sort ZIPs on a single ACS field; ties are broken by ZIP number. Where a page or report filters on several conditions at once (as in the 2026 affordability report), the exact conditions are stated on the page.
• Nearby ZIPs are adjacent and neighboring ZCTAs from the Census TIGER/Line boundary files.
• The affordability and comparison tools use the ZIP-level ACS figures above plus the assumptions stated on each tool; they are planning aids, not quotes.

4. Third-party scores: walkability, schools, safety, cost of living

Four figures on ZIP pages are not Census measures. Walk Score, Bike Score and Transit Score are the 0–100 scores published by Walk Score (walkscore.com). The school rating is an average of GreatSchools.org ratings for schools in the ZIP, on GreatSchools' 1–10 scale. The safety index is a 1–10 scale (10 = safest) derived by the Data Team by inverting Denver Police Department reported-crime statistics per ZIP; it is a relative ranking within Denver, not a rate comparable to other cities. The cost-of-living index is Numbeo's, with 100 = U.S. average. All four were retrieved in March 2026, are labeled where they appear, and are excluded from our metro-wide reports, which use Census figures only.

5. Editorial content

The neighborhood profile on each ZIP page, the FAQs, the neighborhood guides, the blog and every report are written by the Denver Zip Codes Data Team from that area's specific data and local knowledge of the metro. We do not accept sponsored rankings, paid placements or real-estate referral fees, and no page's content is influenced by advertisers. Where we characterize an area, the figures behind the characterization are shown on the same page.

6. Known limitations

• ACS estimates are survey-based with margins of error that grow as population shrinks; several Denver ZIPs are under 20,000 residents, and differences of a few percent between two such ZIPs are not meaningful.
• Median home value is the owner's estimate of what the home would sell for, from the ACS questionnaire, not a transaction price. It lags the market in fast-repricing ZIPs.
• Median gross rent is not in the dataset, so rent burden is not computed anywhere on the site.
• Walk Score, GreatSchools and Numbeo figures are third-party estimates with their own methodologies; the safety index is a within-Denver ranking only.
• ZIP-level medians describe areas, not households.

7. Update schedule

The Census Bureau releases new ACS 5-Year Estimates each December. We rebuild the dataset after each release, re-run every derived figure, ranking and report, and re-review the editorial text on pages whose numbers moved materially. Third-party scores are refreshed on the same cycle. Between annual rebuilds, corrections are applied as they are found.

8. Corrections

If a figure on this site does not match its Census source, or a neighborhood name, county assignment or nearby-ZIP list is wrong, tell us with the ZIP code and the field in question. We verify against the primary source and correct the page; substantive corrections are noted on the affected page. Read more about the site and the team on the About page.