ZIP Code 94603 — Oakland, CA
94603 is a standard (street delivery) ZIP code serving Oakland, California, in Alameda County. To mail something here you only need these five digits — but the four-digit extension narrows delivery to a single point, and it is what USPS bulk postage discounts are priced on.
ZIP code 94603 at a glance
| ZIP code | 94603 |
|---|---|
| Primary city | Oakland |
| State | California (CA) |
| County | Alameda FIPS 06001 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Los_Angeles |
| Population | 35,742 |
| Coordinates | 37.739230, -122.175540 |
How ZIP+4 works in 94603
The four digits after the hyphen encode a delivery segment inside 94603. In practice one segment usually means:
- One side of one block — odd numbers on a street between two cross streets
- A single large building, or one floor of it
- A group of PO boxes, sometimes a single box
- A single business that receives enough mail to warrant its own code
That is why 94603 has no single ZIP+4: two neighbors across the street from each other usually have different ones. Enter a street address above and we will return the exact nine-digit code along with the standardized USPS address format.
Other ZIP codes in Oakland
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 94603.
| ZIP | City | Distance |
|---|---|---|
| 94577 | San Leandro, CA | 1.7 mi |
| 94621 | Oakland, CA | 1.8 mi |
| 94605 | Oakland, CA | 2.1 mi |
| 94613 | Oakland, CA | 2.9 mi |
| 94601 | Oakland, CA | 3.5 mi |
| 94578 | San Leandro, CA | 3.5 mi |
| 94502 | Alameda, CA | 3.6 mi |
| 94619 | Oakland, CA | 3.8 mi |
| 94579 | San Leandro, CA | 3.8 mi |
| 94546 | Castro Valley, CA | 4.6 mi |
| 94602 | Oakland, CA | 4.8 mi |
| 94580 | San Lorenzo, CA | 4.8 mi |
Questions about 94603
What is the ZIP+4 code for 94603?
94603 is the five-digit ZIP code. The ZIP+4 adds four more digits that identify a specific delivery point — usually one side of a city block, a single building, or a group of PO boxes. Because those four digits change from address to address within 94603, you need to look up a specific street address to get them.
What city is 94603?
94603 is assigned to Oakland, California, in Alameda County.
Do I need to use the ZIP+4?
It is optional for ordinary mail, but it speeds up sorting and it is required for most USPS bulk-mail postage discounts. Many address-verification and e-commerce systems also use ZIP+4 to confirm a delivery point exists.
Need thousands of these?
Upload a CSV and get ZIP+4, county, carrier route, and delivery-point data appended to every row — or call the API directly.