63303 ZIP Code, Saint Charles, MO
63303 is a ZIP code in Saint Charles, Missouri in St. Charles County. It covers 20 square miles of land. The closest ZIP codes are 63146, 63043 and 63045. 46,089 people live here in 20,690 households, more than in 9 of every 10 Missouri ZIP codes. At about 2,333 people per square mile it has suburban density, and most homes are owner-occupied (74%). Median household income is $99,138, above the Missouri median of $70,702.
Quick facts
- Mailing city: Saint Charles, MO
- County: St. Charles County
- Land area: 20 sq mi
- Population: 46,089
- Median household income: $99,138
- Carrier routes: 33 (21,072 homes)
Key figures
| Measure | Value |
|---|---|
| Residents | 46,089 |
| Households | 20,690 |
| Median household income | $99,138 |
| Income per person | $58,928 |
| Median age | 41.4 |
| Homeowners | 74.1% |
| Median home value | $321,100 |
| Median rent | $1,374 |
| Bachelor's degree or higher | 48.8% |
| Average commute (minutes) | 21.9 |
| Households with kids under 18 | 22.9% |
| Moved in the past year | 13.6% |
| Below the poverty line | 5.3% |
| Broadband internet | 94.7% |
| Speak a non-English language at home | 7.9% |
Household income
| % of households | Value |
|---|---|
| <$10K | 2.1% |
| $10–15K | 1.5% |
| $15–25K | 2.9% |
| $25–35K | 5.9% |
| $35–50K | 7.8% |
| $50–75K | 17.5% |
| $75–100K | 12.6% |
| $100–150K | 21.1% |
| $150–200K | 11.3% |
| $200K+ | 17.2% |
Age
| % of all residents | Value |
|---|---|
| <10 | 9.8% |
| 10–19 | 9.2% |
| 20–24 | 6.1% |
| 25–34 | 16.0% |
| 35–44 | 13.1% |
| 45–54 | 10.1% |
| 55–64 | 16.5% |
| 65–74 | 11.2% |
| 75+ | 8.1% |
Tenure
| % of housing units | Value |
|---|---|
| Owned, with mortgage | 46.8% |
| Owned outright | 24.9% |
| Rented | 24.5% |
| Vacant | 3.9% |
Type of building
| % of housing units | Value |
|---|---|
| Detached house | 62.4% |
| Townhome | 10.2% |
| 2–4 units | 3.8% |
| 5–19 units | 13.8% |
| 20+ units | 7.3% |
| Mobile / other | 2.4% |
Businesses in 63303
950 business establishments with 11,331 employees (ZIP Codes Business Patterns 2023).
- Health Care and Social Assistance: 135
- Professional, Scientific, and Technical Services: 116
- Construction: 102
- Other Services (except Public Administration): 96
- Accommodation and Food Services: 93
- Retail Trade: 92
- Finance and Insurance: 74
- Administrative and Support and Waste Management and Remediation Services: 63
EDDM carrier routes
63303 has 33 USPS carrier routes with 21,072 residential and 943 business mailboxes. Open the EDDM route map.
Carrier routes in 63303
63303 has 33 USPS carrier routes (28 city (C), 5 rural (R)) with 21,072 residential and 943 business mailboxes. Routes range from 178 homes (C080) to 911 homes (C011); the median route has 686 homes. The Census counted 20,690 households in 63303 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.
| Homes per route | Routes |
|---|---|
| 1–249 | 2 |
| 250–499 | 7 |
| 500–749 | 13 |
| 750–999 | 11 |
| 1,000–1,499 | 0 |
| 1,500+ | 0 |
Best routes in 63303 for…
Most businesses
For B2B offers: office supplies, cleaning, IT, catering and commercial services.
- Route C080 — USPS business mailboxes 185, 178 homes
- Route C051 — USPS business mailboxes 72, 445 homes
- Route C071 — USPS business mailboxes 72, 416 homes
- Route C058 — USPS business mailboxes 71, 481 homes
- Route C043 — USPS business mailboxes 58, 850 homes
Select these 5 routes on the route map
Every carrier route in 63303
| Route | Type | Homes | Businesses | Est. median income | Est. owners | Est. families with kids | Est. moved in past year |
|---|---|---|---|---|---|---|---|
| C011 | City | 911 | 20 | $106,953 | — | — | — |
| C022 | City | 824 | 34 | $56,307 | — | — | — |
| C030 | City | 439 | 30 | $102,125 | — | — | — |
| C034 | City | 506 | 5 | $77,999 | — | — | — |
| C036 | City | 815 | 37 | $68,123 | — | — | — |
| C037 | City | 826 | 9 | $136,562 | — | — | — |
| C040 | City | 756 | 34 | $63,600 | — | — | — |
| C042 | City | 681 | 1 | $122,381 | — | — | — |
| C043 | City | 850 | 58 | $139,987 | — | — | — |
| C045 | City | 483 | 12 | $162,595 | — | — | — |
| C047 | City | 741 | 57 | $59,470 | — | — | — |
| C050 | City | 909 | 20 | $106,030 | — | — | — |
| C051 | City | 445 | 72 | $142,738 | — | — | — |
| C058 | City | 481 | 71 | $75,536 | — | — | — |
| C059 | City | 863 | 56 | $142,738 | — | — | — |
| C060 | City | 870 | 47 | $69,317 | — | — | — |
| C061 | City | 707 | 1 | $102,125 | — | — | — |
| C063 | City | 443 | 1 | $176,239 | — | — | — |
| C065 | City | 713 | 35 | $108,474 | — | — | — |
| C071 | City | 416 | 72 | $102,382 | — | — | — |
| C073 | City | 765 | 37 | $56,307 | — | — | — |
| C076 | City | 546 | 0 | $200,001+ | — | — | — |
| C079 | City | 705 | 0 | $122,381 | — | — | — |
| C080 | City | 178 | 185 | $102,125 | — | — | — |
| C086 | City | 572 | 2 | $104,786 | — | — | — |
| C091 | City | 454 | 0 | $200,001+ | — | — | — |
| C092 | City | 686 | 0 | $104,527 | — | — | — |
| C093 | City | 761 | 11 | $106,953 | — | — | — |
| R011 | Rural | 691 | 2 | $142,738 | — | — | — |
| R021 | Rural | 592 | 3 | $98,999 | — | — | — |
| R024 | Rural | 608 | 0 | $142,738 | — | — | — |
| R032 | Rural | 628 | 28 | $139,987 | — | — | — |
| R044 | Rural | 207 | 3 | $142,738 | — | — | — |
Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 63303 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
- 63146 — Maryland Heights city, MO (4.3 mi)
- 63043 — Maryland Heights city, MO (4.8 mi)
- 63045 — Bridgeton city, MO (4.8 mi)
- 63376 — St. Peters city, MO (5.6 mi)
- 63017 — Chesterfield city, MO (5.8 mi)
- 63044 — Bridgeton city, MO (6.5 mi)
- 63141 — Creve Coeur city, MO (7.4 mi)
- 63304 — Weldon Spring city, MO (8 mi)
Areas that include 63303
- St. Charles, MO ZIP codes — 2 ZIP codes
- Saint Charles, MO ZIP codes — 3 ZIP codes
- St. Charles County ZIP codes — 14 ZIP codes
- Missouri ZIP code data
Where it ranks
- No. 1 of 11: highest share of residents who moved in during the past year in St. Charles County
- No. 4 of 11: highest median age in St. Charles County
Mail every home in 63303
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) 63303, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.
Frequently asked questions
- What city is 63303 in?
- 63303 is a Saint Charles, MO mailing address. By land area, 37% lies inside St. Charles and 4% lies inside St. Peters; the rest is outside any Census-defined city or community.
- What county is 63303 in?
- 63303 is in St. Charles County.
- What is the population of 63303?
- About 46,089 people (±1,436), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 47,292.
- What is the median household income in 63303?
- $99,138 (±$5,566), compared with $70,702 for Missouri as a whole. Half the households in the ZIP code earn more and half earn less.
- How many carrier routes and mailboxes are in 63303?
- 33 USPS carrier routes with 21,072 residential and 943 business mailboxes (22,024 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
- What ZIP codes are near 63303?
- The closest, measured center to center: 63146 (4.3 mi, Maryland Heights), 63043 (4.8 mi, Maryland Heights), 63045 (4.8 mi, Bridgeton), 63376 (5.6 mi, St. Peters), 63017 (5.8 mi, Chesterfield) and 63044 (6.5 mi, Bridgeton).
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.