Zip code format validator

Country

Postal code

Result

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Checks format only - that the code has the shape that country's postal codes take. It cannot confirm the code is a real, currently assigned postal area.

What this checks, and what it cannot

This validates format only - that a code has the shape a country's postal codes actually take, such as five digits for a US ZIP code or the letter-number-letter pattern of a UK postcode. It cannot confirm the code is a real, currently assigned postal area, because that requires an official postal database this tool does not have and does not phone home to.

Why format rules differ so much

Postal code systems were designed independently by each country's postal service, decades apart, for different-sized populations and geographies. US ZIP codes are purely numeric because the system was built around a simple regional/local split. UK postcodes mix letters and numbers because they encode a much finer-grained area and delivery route. A validator built only around "five digits" silently rejects every non-US postcode as invalid - which is the mistake this avoids by asking which country's rules to check against.

Supported formats

United States (5-digit and ZIP+4), United Kingdom, Canada, India (PIN code), Australia, Germany, France and Japan - covering the shapes people most often need to check when validating an address form.