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What Is My ZIP Code?

Your device's location matched to the nearest Census ZIP Code Tabulation Area. It approximates the USPS ZIP and is not a mailing authority.

Last updated

Your browser asks permission first. The lookup runs in your browser. Your exact coordinates stay there; boundary-file requests reveal an approximate area to our host. Covers US states, DC, Puerto Rico and the US island areas. Privacy details.

Or type coordinates

-90 to 90

-180 to 180

Enter the radius reported with these coordinates, if known. Without it, proximity to boundaries cannot be checked. The location button fills it in.

How this is calculated

This page does not test ZIP boundaries. It picks the ZIP area whose centre is nearest to your position, and it prefers areas that overlap your county. That is a weaker method than the point-in-polygon tests on the county, state and city pages, and the page says so each time.

  1. Your browser reports a latitude, longitude and accuracy value. MDN defines the accuracy as a radius in metres at 95% confidence.
  2. The page finds your county with the same boundary test as the county page. A point in no county, such as open water, returns "No ZIP area at this point".
  3. It loads the Census Gazetteer centre point of every ZIP Code Tabulation Area near you and sorts them by distance, using a local flat projection around your position. If the nearest centre is farther away than the area the page has loaded, it returns no ZIP area rather than guess.
  4. Among the eight nearest, it takes the first one that the Census ZCTA-to-county relationship file lists as overlapping your county. If none does, it takes the nearest and says the match is a rough guess.
  5. The note lists up to two other ZIP areas with a nearby centre and their distances, so you can see when the answer is not clear-cut.

The nearest centre is the wrong answer for some positions: a large ZIP area next to a small one can contain a point that is nearer to the small one's centre. Near a boundary, or anywhere you need the mailing ZIP, confirm with the USPS lookup below. Nothing about your position leaves your browser; the page requests only the data files for your area.

ZIP code versus ZCTA

A ZIP code is a USPS routing code for mail delivery. It describes a set of delivery points, not a shape on a map. The Census Bureau builds ZIP Code Tabulation Areas, or ZCTAs, as areas that approximate ZIP codes so it can publish statistics for them. The Census FAQ says ZCTAs should not be used to identify the official USPS ZIP code for mail. For that reason this page labels its answer a ZCTA and calls it the nearest one. ZIP code vs ZCTA goes into the difference.

It follows that a ZIP area can reach into more than one city or county, and that a PO Box-only ZIP may have no area at all. Look up a typed ZIP with the ZIP to county lookup; it shows every county the ZCTA overlaps.

How to confirm your mailing ZIP

For anything that depends on the postal ZIP, use the Postal Service's own ZIP Code lookup with the full street address. This page cannot see addresses, so it can only say which ZIP area your position is probably in.

If the page says the county could not be matched, or the note lists a second ZIP area at nearly the same distance, assume you could be in either and check with the address.

The full card for your position, with county, city and state, is on the home page.

Where the figures come from