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City ZIP codes · California

San Mateo, CA ZIP Codes

5 ZIP codes use the postal name San Mateo, California (Census 2020 ZCTAs and GeoNames postal codes, October 2026): 4 residential and 1 for PO boxes or a single organization. Median household income runs from $122,227 in 94401 to $192,332 in 94404, 1.6 times as much (Census Bureau, ACS 2020-2024). San Mateo's most populous ZIP code is 94403, with 43,276 people (ACS 2020-2024); 97% of its land is in the city of San Mateo.

  • ACS2020-24
  • Census2020
  • GeoNames2026

Where are San Mateo's ZIP codes?

94401: $122k median household income94402: $173k median household income94403: $175k median household income94404: $192k median household income9440294403944049440194401: $122k median household income94402: $173k median household income94403: $175k median household income94404: $192k median household income9440294403944049440194401: $122k median household income94402: $173k median household income94403: $175k median household income94404: $192k median household income94402944039440494401
The 4 residential ZIP codes named San Mateo, shaded by median household income in national fifths (ACS 2020-2024). Select a ZIP to open it. <$54.1k$98.1k+no figure

Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).

How different are San Mateo's ZIP codes?

The highest median household income is in 94404 ($192,332), the lowest in 94401 ($122,227). Home values run from $1,184,500 in 94401 to $2,000,000 or more in 94402.

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013, B25077, B01003).

All 4 residential ZIP codes of San Mateo

Residential ZIP codes with the postal name San Mateo, CA, largest first (ACS 2020-2024); sort by any column
County
94403 San Mateo County 43,276 7,683 $175k $1.75M
94404 San Mateo County 35,881 8,249 $192k $1.71M
94401 San Mateo County 35,295 11,345 $122k $1.18M
94402 San Mateo County 25,475 5,045 $173k $2M+

Download the 5 ZIP codes as CSV

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; 2023 Gazetteer land areas (2020 ZCTAs); town names from simplemaps US ZIP Codes (CC BY 4.0) and GeoNames (CC BY 4.0).

PO Box and single-organization ZIP codes in San Mateo

1 ZIP code named San Mateo has no residential delivery area: post office boxes, or one organization (a large employer, an agency, a university) with its own code. The Census Bureau publishes no figures for them.

San Mateo, CA: ZIP codes without a residential area, for PO boxes or one organization (GeoNames postal codes; USPS does not publish openly which is which)
ZIPCounty
94497San Mateo County

Source: GeoNames postal codes (CC BY 4.0); a ZIP code with no Census ZCTA has no residential delivery area.

Which counties do San Mateo's ZIP codes reach?

San Mateo's residential ZIP codes lie in San Mateo County.

Which places do San Mateo's ZIP codes cover?

A postal name is not a city limit. By the Census Bureau's places, San Mateo's residential ZIP codes cover San Mateo itself and 3 other places, each listed with the ZIP codes that have at least 5% of their land in it or hold most of the place:

  • Baywood Park census-designated 94402
  • Foster City 94404
  • Highlands census-designated 94402

Source: U.S. Census Bureau, 2020 ZCTA-to-place relationship file (shares of land).

Which first three digits do San Mateo's ZIP codes use?

The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Every ZIP code of San Mateo starts with 944.

Three-digit prefixes of San Mateo's ZIP codes, the sectional center for each (USPS labeling list L005, effective October 1, 2026) and how many of the prefix's codes are San Mateo's
PrefixSectional centerHereAll codes
944 San Francisco, CA (SCF 940) 5 5

All 5 ZIP codes that start with 944 are San Mateo's: 4 residential codes and 1 PO Box or unique code, sorted at San Francisco, CA (SCF 940).

Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.