Regex for US ZIP Codes

Read it left to right. Each piece below matches one part of the input:

• ^\d{5} Start of the string and exactly five digits.
• (?:-\d{4})? Optionally a hyphen and the four-digit ZIP+4 add-on.
• $ End of the string.

The whole input must match, from the first character to the last. Every row below is checked against the pattern by our automated test suite before each release.

Because something treated them as numbers. Spreadsheets, CSV imports and <input type="number"> all turn 02134 into 2134, and every ZIP code in Massachusetts, Connecticut, New Jersey, Puerto Rico and much of New England starts with 0. Keep ZIP codes as strings end to end: type="text" with inputmode="numeric" and autocomplete="postal-code" gives a numeric keypad without the conversion.

If you receive data that has already lost zeros, pad it back with zip.padStart(5, "0") before validating, but only when you know the source is US data.

No. Not every five-digit number is assigned (00000 passes this pattern), ZIP codes are delivery routes rather than areas, and they change. To check that a ZIP exists or matches a city and state, use the USPS address APIs or an address-verification service at checkout.

To accept a nine-digit ZIP with or without the hyphen, use ^\d{5}(?:-?\d{4})?$, and normalize to the hyphenated form before storing. For other countries, see the UK postcode and India PIN code patterns.

The pattern is translated for each engine rather than pasted as is: named groups, anchors, escapes, shorthand classes and flags are adjusted so each snippet behaves as closely to the JavaScript version as its engine allows. Differences that remain (Go's RE2 has no lookarounds or backreferences, for example) are called out under each one. The Code tab in the tester above also exports Dart, and updates as you edit the pattern.

JavaScript and TypeScript

const regex = /^\d{5}(?:-\d{4})?$/;

function isValid(value) {
  return regex.test(value);
}

console.log(isValid("90210"));

Python

import re

pattern = re.compile(r"^[0-9]{5}(?:-[0-9]{4})?\Z")

def is_valid(value: str) -> bool:
    return pattern.search(value) is not None

print(is_valid("90210"))

• \d and \w are written as [0-9] and [A-Za-z0-9_] because in Python they also match digits and letters from other scripts.
• JavaScript's $ only matches at the very end of the string. Python's $ also matches before a trailing newline, so the pattern uses \Z instead.

Go

package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`^\d{5}(?:-\d{4})?$`)
	fmt.Println(re.MatchString("90210"))
}

C#

using System;
using System.Text.RegularExpressions;

// The timeout stops a pathological input from hanging the thread (ReDoS).
var regex = new Regex(@"^[0-9]{5}(?:-[0-9]{4})?\z", RegexOptions.None, TimeSpan.FromSeconds(1));
Console.WriteLine(regex.IsMatch("90210"));

• \d and \w are written as [0-9] and [A-Za-z0-9_] because in .NET they also match digits and letters from other scripts.
• JavaScript's $ only matches at the very end of the string. .NET's $ also matches before a trailing newline, so the pattern uses \z instead.

PHP

<?php

$pattern = '/^\d{5}(?:-\d{4})?$/D';

function isValid(string $value, string $pattern): bool
{
    return preg_match($pattern, $value) === 1;
}

var_dump(isValid('90210', $pattern));

• The D modifier makes $ match only at the very end, like JavaScript (PCRE's $ also matches before a trailing newline).

• Regex for UK Postcodes: All six UK postcode formats, with or without the space, including SW1A 1AA.
• Regex for Indian PIN Codes: Six-digit Indian postal codes that never start with 0, with an optional space.
• Regex for Phone Numbers (E.164 Format): International numbers in E.164: a plus, a country code and up to 15 digits in total.
• Regex for Numbers Only: Digits only, plus variants for signs, decimals and thousands separators.

Browse all 25 patterns in the regex pattern library, or build your own in the regex tester.