ZIP Code Regex (Postal Code Patterns by Country)

Postal codes differ completely between countries: five digits in the US (or ZIP+4), letter-digit-letter in Canada, the irregular outward/inward codes of the UK, 4 digits plus 2 letters in the Netherlands, five digits in Korea since 2015. This tool gives a tested regex for each of 35 formats with code for JavaScript, PHP, Python, Java, C# or an HTML pattern attribute, checks a list of codes, and can tell you which countries a code fits.

How to use this tool

1. Choose the country (or "All" to identify a code).
2. Choose the language and whether lower-case letters are accepted.
3. Paste the codes to check, one per line.
4. Copy the regex or the code snippet.

Formula

US: [0-9]{5}(?:[ -][0-9]{4})? · Canada: [A-Z][0-9][A-Z] ?[0-9][A-Z][0-9] (restricted letters) · UK: outward code ?[0-9][A-Z]{2}

Patterns follow the formats published by the postal operators and Google's address metadata (libaddressinput), including letter restrictions where they are documented — Canada never uses D, F, I, O, Q or U, Dutch codes never end in SA, SD or SS, Spanish codes start with a province number 01–52, Indian PINs never start with 0. Values are trimmed; inner spaces must be single. A pattern checks the format only: 99999 is a well-formed US ZIP that does not exist.

Example

For the United States the sample gives 3 matches: 90210, 90210-1234 and 90210 1234. 9021 has only four digits, 12345-123 has a three-digit extension, and SW1A 1AA is a British postcode — the tester says so. Switched to the UK, SW1A 1AA, W1A 0AX and DN55 1PT all match, while SW1A 1A is incomplete.