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 ZIPs the two match closely; they diverge for post-office-box and single-use ZIPs. Scope: this site covers 30 ZIPs in the City of Miami and Miami Beach (USPS city names), 33101 through 33157, not the roughly 100 ZIPs of Miami-Dade County. Hialeah, Coral Gables, Doral, Homestead, Miami Gardens and the rest of the county are outside the dataset, and the Miami-Dade County page describes only the ZIPs on this site. Every "of N" rank and every median on this site refers to this 30-ZIP urban core, not to the county or the metro.

2. ZIPs without demographics

One of the 30 ZIPs, 33101, is a PO Box ZIP serving the downtown Miami post office; it has no ZCTA and no Census population, income or housing estimate. Its page says so instead of showing zeros, points to the nearest delivery ZIPs that do carry data, and it is excluded from every median, rank and report. That leaves 29 ZIPs with full housing data, which is the population every "of 29" rank on this site refers to. Fisher Island (33109) reports no median rent (almost no rental units), so its rent-to-income ratio is not computed.

3. Primary source: ACS 5-Year Estimates

Population, density, median age, sex ratio, median household income, per-capita income, median home value, median gross rent, owner- and renter-occupancy, total housing units, high-school and bachelor's attainment (population 25 and over), poverty rate, unemployment, and land and water area come from the U.S. Census Bureau's American Community Survey (ACS) 5-Year Estimates, retrieved from data.census.gov at the ZCTA level. 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. A 5-year estimate describes the average condition across the collection window rather than a single point in time. Each field maps to a standard ACS detailed table — B01003 for population, B19013 for median household income, B19301 for per-capita income, B25077 for median home value, B25064 for median gross rent, B25003 for tenure, B17001 for poverty, B15003 for educational attainment, B23025 for employment status and B01002 for median age — so any figure can be checked directly on data.census.gov by table and ZCTA.

4. The $2,000,001 and $250,001 caps

The ACS top-codes median home value at $2,000,001 and median household income at $250,001. 1 ZIP on this site sits at both caps: Fisher Island (33109) reports a median home value of $2,000,001 and a median household income of $250,001, so its ratio is a floor and its true figures are far higher. No other ZIP on this site is capped. Their true medians are higher, so any ratio computed from a capped value is a floor. Our reports and per-ZIP profiles mark these with "at least" or a plus sign; ZIP pages show the capped value as the Census reports it.

5. Figures we compute ourselves

• Price-to-income ratio = median home value ÷ median household income. 3.0 is the long-run U.S. norm; ratios above 5.0 are conventionally described as severely unaffordable. The median ZIP on this site is currently 7.8. In Brickell, downtown and Miami Beach the owner-occupied stock is largely condominium, so the home value describes condos rather than houses.
• Rent-to-income ratio = (median gross rent × 12) ÷ median household income, as a percentage. Above 30% is "cost-burdened" and above 50% "severely cost-burdened" under the U.S. Department of Housing and Urban Development definitions. Both ratios use ZIP-level medians and describe the area, not any individual household.
• Metro and city benchmarks are medians across the ZIPs in scope with each ZIP weighted equally, not population-weighted. City and county populations are the sum of their ZIPs' ACS populations.
• Ranks ("N of 29") sort every ZIP with housing data on a single ACS field, 1 = highest. City affordability ranks sort the ZIPs sharing a USPS city name (Miami or Miami Beach) on price-to-income, 1 = lowest ratio.
• Nearby ZIPs are the closest entries in the dataset by straight-line distance between ZIP centroids.
• Density bands in the written profiles (high-rise, mixed urban, single-family, low-density) are fixed thresholds on residents per square mile: 18,000, 8,000 and 3,000. Density is population divided by ACS land area.

6. Editorial content

The description, FAQs and "Affordability & Profile" section on each ZIP page, the "at a glance" overview on the city and county pages, and every report are generated by the Miami Zip Codes Data Team from that area's specific figures and reviewed before publication; each sentence is conditional on the numbers, so two areas with different data read differently. We do not accept sponsored rankings, paid placements or real-estate referral fees, and no page's content is influenced by advertisers. Crime, school and walkability scores are not published on this site: the ACS does not collect them, and ZIP-level versions from third parties are not consistently available for the area.

7. Known limitations

• ACS estimates are survey-based with margins of error that grow as population shrinks. Fisher Island (33109, about 800 residents) and the airport-edge ZIP 33122 (about 1,900) carry wide margins; small differences involving such ZIPs are not meaningful, and the report restricts rankings to ZIPs above a stated population floor.
• Median home value is the owner's estimate from the ACS questionnaire for owner-occupied units only, not a transaction price, and is capped at $2,000,001. In condominium-heavy ZIPs (Brickell, downtown, South Beach) it reflects condo prices, and in ZIPs where only a few percent of households own (33128, 33122) it describes a very small sub-market.
• Median gross rent includes utilities and covers all occupied rental units, including long-tenured and rent-controlled leases, so it runs below current asking rents in Miami, one of the fastest-rising rental markets in the country over the survey window.
• ZIPs dominated by public housing (parts of 33136 and 33128) or by a single use show medians that describe residents, not the buyer or renter pool.
• USPS city names are used: "Miami" ZIPs include unincorporated Miami-Dade areas and neighborhoods such as Coconut Grove, Little Havana and Kendall that appear under the Miami post office. Neighborhood names are not part of the dataset.
• ZIP-level medians describe areas, not households.

8. 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, profile and report, and re-review pages whose numbers moved materially. Between annual rebuilds, corrections are applied as they are found.

9. Corrections

If a figure on this site does not match its Census source, or a city or county assignment, ZIP type, nearby-ZIP list or description 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 and on the About page.