United States
How to Find a ZIP Code in the United States
Practical steps to find the correct ZIP code for an American address, how to verify it, and what to do when a place seems to have more than one.
Updated 14 October 2026 · 3 min read
The most reliable way to find a ZIP code is to ask the United States Postal Service's own lookup tool using the full street address. Because ZIP codes follow delivery routes, a street name or a city name alone is frequently not enough.
Start from the full address
Gather the street number, street name (including any direction such as North or West), city and state. Enter these into the national postal operator's ZIP code lookup or address verification tool. It returns the five-digit code, and usually the ZIP+4 extension, for that exact delivery point.
If you are looking for a code for a whole town, the same tool can list the ZIP codes assigned to a city. Expect more than one in any large town.
Other places to check
- Existing mail. A recent letter, bill or parcel label from the address is the quickest confirmation.
- The recipient. Ask them to read the code from their own mailing address; they are using it daily.
- The business or building. Large organizations, universities and government offices may have their own unique ZIP code, and they usually print it on their website or contact page.
- A map service. Many map and navigation apps show a ZIP code in the address details, but treat it as a hint and confirm against the postal operator when it matters.
How to verify
Confirm that the street number actually exists on that street, that the city name matches the postal city (which can differ from the local name people use), and that the state abbreviation is correct. A good test is to look up the address, then compare the returned standardized version with what you were given. Differences in unit number, direction or city name signal a problem.
If you are unsure
- Do not guess the ZIP+4 extension. The five-digit code alone is accepted for delivery.
- If an address sits on the border between two areas, trust the postal operator's lookup result over your own reading of a map.
- For a new building or development, the code may be assigned only after the address is registered, so ask the developer or the local post office.
When an address is not enough
Some places are hard to describe in words: a farm gate, an entrance behind a building, or a pickup point. In those cases, you can pair the address with a UPCS exact-location code. It sits next to the ZIP code, not in place of it. You can read how it works in the United States overview, or see the ZIP code structure and the address layout.
Frequently asked questions
Can two addresses on the same street have different ZIP codes?
Yes. ZIP codes follow delivery routes, and a street can pass through the boundary of two codes. Always look up the full street address, not just the street name.
What if I only know the city?
A city often has many ZIP codes, so the city name alone is not enough. You need the street address, or the nearest known address, to find the right one.