94403 ZIP Code, San Mateo, CA
94403 is a ZIP code in San Mateo, California in San Mateo County. It covers 5.6 square miles of land. The closest ZIP codes are 94402, 94002 and 94404. 43,276 people live here in 16,414 households. At about 7,683 people per square mile it is built up to city-neighborhood density, and owners and renters are mixed (53% own). Median household income is $174,917, well above the California median of $99,122.
Quick facts
- Mailing city: San Mateo, CA
- County: San Mateo County
- Land area: 5.6 sq mi
- Population: 43,276
- Median household income: $174,917
- Carrier routes: 32 (18,180 homes)
Key figures
| Measure | Value |
|---|---|
| Residents | 43,276 |
| Households | 16,414 |
| Median household income | $174,917 |
| Income per person | $88,226 |
| Median age | 38.9 |
| Homeowners | 52.5% |
| Median home value | $1,746,300 |
| Median rent | $3,263 |
| Bachelor's degree or higher | 60.6% |
| Average commute (minutes) | 26.3 |
| Households with kids under 18 | 28.8% |
| Moved in the past year | 18.6% |
| Below the poverty line | 6.6% |
| Broadband internet | 96.7% |
| Speak a non-English language at home | 46.5% |
Household income
| % of households | Value |
|---|---|
| <$10K | 4.9% |
| $10–15K | 1.0% |
| $15–25K | 1.6% |
| $25–35K | 3.6% |
| $35–50K | 4.3% |
| $50–75K | 7.6% |
| $75–100K | 6.5% |
| $100–150K | 14.3% |
| $150–200K | 10.9% |
| $200K+ | 45.3% |
Age
| % of all residents | Value |
|---|---|
| <10 | 10.1% |
| 10–19 | 9.9% |
| 20–24 | 5.4% |
| 25–34 | 16.8% |
| 35–44 | 16.8% |
| 45–54 | 13.4% |
| 55–64 | 11.3% |
| 65–74 | 8.2% |
| 75+ | 8.1% |
Tenure
| % of housing units | Value |
|---|---|
| Owned, with mortgage | 34.7% |
| Owned outright | 14.3% |
| Rented | 43.3% |
| Vacant | 7.7% |
Type of building
| % of housing units | Value |
|---|---|
| Detached house | 47.2% |
| Townhome | 9.2% |
| 2–4 units | 6.5% |
| 5–19 units | 14.4% |
| 20+ units | 22.7% |
| Mobile / other | 0.0% |
Businesses in 94403
1,204 business establishments with 32,578 employees (ZIP Codes Business Patterns 2023).
- Health Care and Social Assistance: 183
- Professional, Scientific, and Technical Services: 173
- Retail Trade: 164
- Accommodation and Food Services: 133
- Other Services (except Public Administration): 112
- Construction: 76
- Real Estate and Rental and Leasing: 76
- Finance and Insurance: 66
EDDM carrier routes
94403 has 32 USPS carrier routes with 18,180 residential and 1,117 business mailboxes. Open the EDDM route map.
Carrier routes in 94403
94403 has 32 USPS carrier routes (32 city (C)) with 18,180 residential and 1,117 business mailboxes. Routes range from 355 homes (C032) to 939 homes (C015); the median route has 516 homes. The Census counted 16,414 households in 94403 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.
| Homes per route | Routes |
|---|---|
| 1–249 | 0 |
| 250–499 | 13 |
| 500–749 | 15 |
| 750–999 | 4 |
| 1,000–1,499 | 0 |
| 1,500+ | 0 |
Best routes in 94403 for…
Most businesses
For B2B offers: office supplies, cleaning, IT, catering and commercial services.
- Route C023 — USPS business mailboxes 221, 429 homes
- Route C053 — USPS business mailboxes 193, 493 homes
- Route C001 — USPS business mailboxes 93, 747 homes
- Route C012 — USPS business mailboxes 84, 381 homes
- Route C009 — USPS business mailboxes 67, 814 homes
Select these 5 routes on the route map
Every carrier route in 94403
| Route | Type | Homes | Businesses | Est. median income | Est. owners | Est. families with kids | Est. moved in past year |
|---|---|---|---|---|---|---|---|
| C001 | City | 747 | 93 | $178,642 | — | — | — |
| C004 | City | 370 | 2 | $124,312 | — | — | — |
| C007 | City | 460 | 3 | $200,001+ | — | — | — |
| C009 | City | 814 | 67 | $200,001+ | — | — | — |
| C011 | City | 513 | 1 | $107,534 | — | — | — |
| C012 | City | 381 | 84 | $111,145 | — | — | — |
| C013 | City | 525 | 55 | $185,126 | — | — | — |
| C014 | City | 458 | 37 | $185,126 | — | — | — |
| C015 | City | 939 | 38 | $200,001+ | — | — | — |
| C016 | City | 421 | 45 | $109,701 | — | — | — |
| C017 | City | 472 | 10 | $103,540 | — | — | — |
| C019 | City | 449 | 8 | $200,001+ | — | — | — |
| C021 | City | 478 | 10 | $107,534 | — | — | — |
| C022 | City | 519 | 0 | $192,840 | — | — | — |
| C023 | City | 429 | 221 | $185,126 | — | — | — |
| C024 | City | 647 | 0 | $192,840 | — | — | — |
| C025 | City | 472 | 1 | $200,001+ | — | — | — |
| C026 | City | 512 | 8 | $200,001+ | — | — | — |
| C027 | City | 792 | 25 | $137,231 | — | — | — |
| C029 | City | 675 | 46 | $200,001+ | — | — | — |
| C030 | City | 851 | 21 | $200,001+ | — | — | — |
| C032 | City | 355 | 1 | $192,840 | — | — | — |
| C033 | City | 613 | 0 | $164,283 | — | — | — |
| C034 | City | 736 | 62 | $107,534 | — | — | — |
| C035 | City | 748 | 33 | $200,001+ | — | — | — |
| C037 | City | 509 | 16 | $200,001+ | — | — | — |
| C047 | City | 557 | 1 | $170,527 | — | — | — |
| C048 | City | 569 | 6 | $200,001+ | — | — | — |
| C049 | City | 396 | 0 | $200,001+ | — | — | — |
| C050 | City | 643 | 2 | $150,400 | — | — | — |
| C051 | City | 637 | 28 | $57,326 | — | — | — |
| C053 | City | 493 | 193 | $200,001+ | — | — | — |
Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 94403 on the EDDM route map.
How route demographics are estimated
Mailbox counts come from USPS; demographics are estimates
The number of homes and businesses on each carrier route is the current USPS EDDM count. The Census Bureau does not publish figures for carrier routes, so income, homeownership, ages, families, movers and housing age on a route are EDDM2GO estimates built from Census block groups (neighborhood areas of roughly 600 to 3,000 people).
How a route gets its figures: the block-group length-share method
We trace each route's streets every 25 meters and record which block group each stretch falls in. The route's homes are spread along its streets in proportion to length, so a route with 60% of its street length in one block group is assumed to have 60% of its homes there. Each block group then contributes its Census counts in proportion to the share of its housing units that sit on the route (capped at the whole block group). Medians are recalculated from the combined income, home-value and age brackets, the way the Census Bureau computes them, not averaged.
Margins of error
Census survey figures carry a margin of error at 90% confidence; we carry it through the calculation and show it as ±. Our margins treat the route-to-block-group split as exact, so the real uncertainty is larger. Routes with fewer than 100 estimated households, large margins, or streets we could not place are flagged.
Different years
USPS mailbox counts are current. Census figures are 5-year averages for 2020–2024, so a new subdivision may have more homes on the route today than the Census counted. Use the route figures to compare routes with each other, not as an exact head count.
Why some routes show identical figures
Two routes that run through the same block group get the same percentages and medians, because the Census publishes one set of figures for the whole block group. Their mailbox counts still differ, and those are exact.
Route and mailbox counts: USPS EDDM route data. Route demographics: EDDM2GO estimates from U.S. Census Bureau American Community Survey 5-year block-group data (2020–2024) and 2024 cartographic block-group boundaries. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.
Nearby ZIP codes
- 94402 — San Mateo city, CA (1.4 mi)
- 94002 — Belmont city, CA (1.8 mi)
- 94404 — Foster City city, CA (2.4 mi)
- 94401 — San Mateo city, CA (2.7 mi)
- 94065 — Redwood City city, CA (3.1 mi)
- 94070 — San Carlos city, CA (3.4 mi)
- 94010 — Hillsborough town, CA (4.5 mi)
- 94061 — Redwood City city, CA (6.5 mi)
Areas that include 94403
- San Mateo, CA ZIP codes — 4 ZIP codes
- San Mateo County ZIP codes — 31 ZIP codes
- California ZIP code data
Where it ranks
- No. 1 of 28: highest share of residents who moved in during the past year in San Mateo County
- No. 4 of 28: lowest median age in San Mateo County
Mail every home in 94403
Route counts on this page price as Full Service 6.5 × 9 postcards: we print, bundle by carrier route and hand the mailing to USPS. Prefer to take it to the Post Office yourself? Print only costs less and you pay postage at drop-off.
EDDM guides
ZIP code statistics describe the Census ZIP Code Tabulation Area (ZCTA) 94403, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.
Frequently asked questions
- What city is 94403 in?
- 94403 is a San Mateo, CA mailing address. By land area, 97% lies inside San Mateo; the rest is outside any Census-defined city or community.
- What county is 94403 in?
- 94403 is in San Mateo County.
- What is the population of 94403?
- About 43,276 people (±1,493), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 45,057.
- What is the median household income in 94403?
- $174,917 (±$15,671), compared with $99,122 for California as a whole. Half the households in the ZIP code earn more and half earn less.
- How many carrier routes and mailboxes are in 94403?
- 32 USPS carrier routes with 18,180 residential and 1,117 business mailboxes (19,297 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
- What ZIP codes are near 94403?
- The closest, measured center to center: 94402 (1.4 mi, San Mateo), 94002 (1.8 mi, Belmont), 94404 (2.4 mi, Foster City), 94401 (2.7 mi, San Mateo), 94065 (3.1 mi, Redwood City) and 94070 (3.4 mi, San Carlos).
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.