ZIP Code 45403 — Dayton, OH
45403 is a standard (street delivery) ZIP code serving Dayton, Ohio, in Montgomery 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 45403 at a glance
| ZIP code | 45403 |
|---|---|
| Primary city | Dayton |
| State | Ohio (OH) |
| County | Montgomery FIPS 39113 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 13,608 |
| Coordinates | 39.763030, -84.149780 |
How ZIP+4 works in 45403
The four digits after the hyphen encode a delivery segment inside 45403. 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 45403 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 Dayton
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 45403.
| ZIP | City | Distance |
|---|---|---|
| 45410 | Dayton, OH | 1.2 mi |
| 45404 | Dayton, OH | 1.9 mi |
| 45423 | Dayton, OH | 2.2 mi |
| 45469 | Dayton, OH | 2.2 mi |
| 45402 | Dayton, OH | 3.1 mi |
| 45420 | Dayton, OH | 3.2 mi |
| 45419 | Dayton, OH | 3.5 mi |
| 45409 | Dayton, OH | 3.5 mi |
| 45431 | Dayton, OH | 3.7 mi |
| 45432 | Dayton, OH | 3.7 mi |
| 45405 | Dayton, OH | 4.1 mi |
| 45435 | Dayton, OH | 4.8 mi |
Questions about 45403
What is the ZIP+4 code for 45403?
45403 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 45403, you need to look up a specific street address to get them.
What city is 45403?
45403 is assigned to Dayton, Ohio, in Montgomery 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.