Census ACS · ZIP Code Tabulation Area
St. Louis County, Missouri
$42,701
Median household income ($42,701) is lower than St. Louis County County ($93,939).
$59,662
Average household income ($59,662) is lower than St. Louis County County ($123,879).
$27,628
Per-capita income ($27,628) is lower than St. Louis County County ($51,642).
County and peer ZIP comparisons use population-weighted aggregates from other ZCTAs in the same county. Source: US Census Bureau ACS 5-year estimates. Page URL: https://resource.skyrocketbpo.com/tools/market-research/us-income-demographics-by-zip-code/missouri/63121
Permanent URL backed by Census ACS data in PocketBase.
Context & methodology
ZIP Code Tabulation Area 63121 in Missouri is defined by the U.S. Census Bureau for statistical reporting. It closely matches USPS ZIP code 63121 but may differ slightly at edges — use these ACS figures as demographic benchmarks, not exact postal boundaries.
An estimated 25,008 people live in this ZCTA. Median household income here ($42,701) is lower than St. Louis County County ($93,939). Operators sizing a local market often pair median income with mean income ($59,662) and the share of households earning $100k+ to gauge both typical and upscale demand.
The neighboring ZIP comparison table above lists adjacent ZCTAs with their own ACS estimates. Large gaps between adjacent ZIP codes are common — a few miles can separate very different income profiles, which matters for retail trade areas, service radius, and competitive positioning.
Small-area ACS estimates carry wider margins of error than state or county totals. The Census Bureau publishes guidance on interpreting confidence intervals (linked below). When a figure is critical to your analysis, download the underlying table from data.census.gov and review the margin of error column before citing it in a business plan or press release.
Data vintage: Census ACS 2024 5-year estimates (published 2026). Tables: B19013 (median HH income), B19001 (distribution), B19049 (income by age of householder).
Primary government data and reference pages for verifying and extending this analysis.
Official overview of the ACS — the primary source for annual household income, demographics, and housing estimates at state, county, and ZIP Code Tabulation Area levels.
Guidance on margins of error, sampling, and when to use 1-year vs. 5-year estimates — essential for interpreting small-area income data.
Explains how Census ZCTAs relate to USPS ZIP codes and why income figures may differ slightly from postal boundaries.
Official ACS estimate for this ZCTA on data.census.gov — compare directly to the figure on this page.
ACS Data Profile with income, employment, poverty, and housing for ZIP Code Tabulation Area 63121.
County-level median income for comparison with ZIP 63121.
Statewide income and demographic context for Missouri.
State-level income distribution to compare against this ZIP.
Labor market and wage trends for Missouri.
Combine ZIP-level income with these free Resource tools for fuller market pictures.