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ZIP code regex tester

Test US ZIP, ZIP+4, Canadian, UK and other postal codes against a ready regex, one value per line, then copy the JavaScript regex, the HTML pattern attribute or a Python snippet.

Postal code patterns by country

The HTML ZIP code input

<label for="zip">ZIP code</label>
<input id="zip" name="zip" inputmode="numeric" autocomplete="postal-code" pattern="\d{5}(-\d{4})?" title="5-digit ZIP or ZIP+4, like 02134 or 02134-1234" required>

The pattern attribute has no ^ or $: the browser matches it against the whole value. inputmode="numeric" opens the number keypad on phones, and autocomplete="postal-code" lets autofill fill the field.

Why not type=number?

A number input stores a number, and numbers have no leading zeros: 02134 becomes 2134, which is a different (invalid) ZIP. It also rejects the hyphen in ZIP+4 and adds spinner arrows. ZIP codes are text that happens to contain digits.

Normalise on the server

Browser checks are easy to skip, so check again on the server, and clean the value before you match and store it: trim spaces, uppercase letters, and add the space in Canadian codes so k1a0b1 is stored as K1A 0B1.

function normaliseCanadianPostal(value) {
  const v = value.trim().toUpperCase().replace(/\s+/g, "");
  return v.length === 6 ? `${v.slice(0, 3)} ${v.slice(3)}` : v; // "k1a0b1" → "K1A 0B1"
}

A regex checks format only. It can't tell you that a ZIP or postcode exists or matches the street address; that needs an address lookup.

ZIP code regex FAQ