Any US ZIP to city, state and coordinates — live lookup, plus how ZIP codes actually work
Lookups query the free Zippopotam.us service — the ZIP you enter (and nothing else) is sent to it. Results cover all US ZIP codes.
| Digit(s) | Meaning | Yours |
|---|
Enter a ZIP and hit Look Up.
A ZIP code is a routing instruction wearing a location costume — five digits that tell the USPS which truck, not where you live. That distinction explains most ZIP-related confusion: codes without boundaries, cities that don't match, and coordinates that land in a lake. This lookup resolves any US ZIP to its city, state and center-point coordinates via a live query, and decodes the digit structure so the number itself becomes readable.
| Piece | Meaning |
|---|---|
| First digit (0–9) | National zone, roughly east (0) to west (9) — 0 is New England, 9 is the Pacific |
| Digits 2–3 | The sectional center facility — the regional hub your mail sorts through |
| Digits 4–5 | The local post office or delivery area |
| ZIP+4 | A block face, building, or high-volume recipient — optional, speeds machine sorting |
Sales-tax jurisdiction sanity checks (though tax boundaries follow government lines, not ZIPs — the classic e-commerce miscalculation), shipping-zone estimates, demographic lookups, form validation, and settling the "is that address real" question. For radius math between two ZIPs, the coordinates here plug straight into a haversine distance — or just eyeball it: one degree of latitude is ~69 miles.
The USPS assigns one 'default' place name per ZIP — often the town whose post office runs your routes, not your municipality. Your city is usually on the ZIP's 'acceptable names' list even when it isn't the default; mail works either way.
About 40 do — mostly rural routes served from an office across the border (e.g., ZIPs along the TX/NM and VA/TN lines). The lookup returns the primary state; for tax or legal purposes, the ADDRESS's state governs, never the ZIP's.
The +4 identifies a block face or building side for machine sorting. You never need it — modern sorting derives it from the street address anyway. Bulk mailers use it for postage discounts; humans can ignore it.
Three reasons: unassigned ranges (plenty of five-digit combinations simply aren't ZIPs), 'unique' ZIPs assigned to single organizations (universities, agencies, big companies) that aren't in public place datasets, and PO-box-only ZIPs with no residential geography.
They're the ZIP's population-weighted center — typically within a few miles of any address in it. Good for distance estimates, store-locator radii and mapping dots; not for driving directions. Dense urban ZIPs are tight; rural ZIPs can span 50+ miles.
Occasionally — the USPS splits fast-growing areas (new suburbs get carved new ZIPs), retires and reassigns codes, and realigns boundaries as routes change. That's why geocoding databases carry vintage dates and why decade-old ZIP lists misfire.
The ZIP you type is sent to the free Zippopotam.us API to fetch the result — that's the entire transmission. No other data leaves your browser, and nothing is stored.
Five digits, three routing layers, zero boundaries — the ZIP is the most-misread number in American addresses. Now it reads back: zone, hub, office, done.