AddressLab

AddressLab

Postal Code Format Checker

Check whether a postal code matches the basic written format used by the selected country or region. The browser-based checker normalizes common capitalization, spacing, and separator differences, then shows the normalized value. It does not query a postal database or confirm that a code is assigned, active, deliverable, or connected to a real address.

Check a postal code format

Choose a country or region, enter a postal code, check its syntax, and copy the normalized result. All processing stays in the browser.

Try an example
Enter a postal code to check its format

The checker normalizes spacing, capitalization, and separators.

Expected format10001 or 10001-1234

Format check only. A valid pattern does not confirm that a postal code is assigned, active, or deliverable.

Use cases

  • Test postal-code fields, input masks, validation messages, and checkout forms with country-specific syntax.
  • Normalize common spacing, capitalization, and separator variations before comparing QA results.
  • Prepare documented examples for product specifications, test cases, support articles, and localization reviews.
  • Check international form behavior without sending entered values to an address-validation service.

Supported regions and formats

United StatesCanadaUnited KingdomJapanAustraliaGermanyIndiaTurkeyNigeriaHong Kong, China

Address format notes

  • Select the country or region before checking because postal-code lengths and character rules differ.
  • The checker validates syntax only. A matching pattern does not prove that the code is assigned, current, or deliverable.
  • Hong Kong does not use a general postcode system; forms should normally allow its postcode field to remain empty.
  • Do not enter names, street addresses, account details, or other personal information. Only the postal-code value is needed.

How normalization works

The checker applies Unicode compatibility normalization, trims surrounding whitespace, standardizes capitalization where letters are used, and restores common separators such as the space in a Canadian or UK postcode and the hyphen in a Japanese postal code. Unexpected letters or punctuation are not silently converted into a valid numeric code.

What a valid result means

A valid result means the normalized value matches the selected country or region's general postal-code syntax. It does not mean the code appears in an official postal directory, covers the rest of the address, or can receive mail.

How to use the result in form testing

Test both accepted and rejected values, switch countries without clearing the field, verify empty-field handling, and confirm that your application preserves leading zeroes. Compare frontend validation with backend rules so the same value is not accepted in one layer and rejected in another.

How this page was checked

Last format review:

What we checked

  • Country-specific character, length, spacing, and separator patterns
  • Normalization behavior for common capitalization and separator differences
  • The distinction between syntax matching and official assignment or deliverability
  • Hong Kong's normal absence of a postcode

Primary references

Data boundary: This tool performs a local syntax check only. It does not query the referenced postal operators, confirm that a code is assigned or current, match a code to a locality or street, or verify delivery. Do not enter a full address or personal information. Read the data methodology and editorial standards

Not for

Generated data is for testing, development, education, and prototypes only. Do not use it for delivery, impersonation, fraud, or bypassing platform rules.

  • Do not use generated records as real delivery destinations.
  • Do not use generated identities, addresses, or email fields for fraud, impersonation, spam, or platform rule bypassing.
  • Do not enter passwords, production credentials, payment data, or personal information into test records.

FAQ

Does this checker verify that a postal code exists?

No. It checks the written pattern only and does not query an official postcode directory.

Is the value sent to a server?

No. Normalization and format checking run in your browser.

Why can a correctly formatted code still be unusable?

A code may be unassigned, retired, mistyped for the intended locality, or insufficient to prove that an address is deliverable.

Does Hong Kong have a postal code?

Hong Kong does not use a general postcode system. International forms should normally permit the postcode field to be empty for Hong Kong addresses.

Which formats are supported?

The checker covers the United States, Canada, United Kingdom, Japan, Australia, Germany, India, Turkey, Nigeria, and Hong Kong.