How to validate a postal code format
Start by choosing the country or region printed on the address. The Postal Code Validator then checks one postal/ZIP code or a pasted list against that selection. It trims input, applies the selected rule's spacing and casing normalization, and reports Valid format, Invalid format, or Unsupported.
- Choose Single Code for one value or Bulk Codes for a list.
- Select a supported country or region in Country or region.
- Enter one candidate in Postal/ZIP code, or paste candidates into Postal/ZIP codes.
- Read the status, normalized value, expected format, example, and errors.
- For a bulk check, choose Copy CSV or Download CSV after the results appear.
How to check ZIP code format for one country
Choose Single Code, select Country or region, and enter a value in Postal/ZIP code. The result shows the selected region, expected format, example, and normalized value. A candidate that fails the selected pattern receives Invalid format, with the rule and example listed under Errors.
What postal code normalization changes
Normalization trims the value and applies the spacing, separator, and letter-case rules defined for the selected region. For Canada, letters are uppercased, spaces and hyphens are removed before checking, and the standard space is restored:
Input: k1a0b1
Country or region: Canada
Normalized value: K1A 0B1
Status: Valid formatOther regions use their own pattern. Poland, for example, normalizes five digits into the 00-950 shape. A five-digit rule such as Germany's keeps the value as five digits.
How bulk postal code validation handles duplicates and unsupported input
Choose Bulk Codes and put values in Postal/ZIP codes, one per line or separated by commas. Empty entries are skipped. Each remaining value gets a row with Code, Region, Status, Duplicate, and Errors. Once results appear, Copy CSV and Download CSV become available.
Duplicates stay in the results. A later value is flagged when its normalized value matches an earlier value, so 90210 and 90210 can point to the same earlier row after trimming.
Selecting Other / not listed returns Unsupported and applies no pattern. Leaving Country or region unselected also returns an unsupported result. Empty input produces no result until a usable value is entered. An entered value that fails a supported rule shows the rule and its example as an error.
Validation checks structure only. It does not confirm that a code exists, resolve or complete an address, or extract codes from free text. The checks run in the browser, and the page makes no request with submitted codes to a postal or mapping service.
Examples for single and bulk checks
A developer checking a checkout form can test sample values in Single Code, then compare the normalized value and expected format with the form's rules.
For data cleanup, put extracted postal codes into Bulk Codes, review invalid and duplicate rows, and download the CSV for the next step.
A support worker reviewing an address record can select its stated country and check the supplied postal code against that country's structural rule before asking for a correction.
Choose the validator that matches the data
Choose Data Validation Tools when you need to pick a focused validator for a submitted value. Use the Email Validator when the input is an email address and you need email-specific syntax or domain checks. Use the IP Address Validator & Bulk Lookup Tool for IPv4, IPv6, or CIDR-style input and its classification results. Use the VAT Number Validator when you need a VAT country prefix, length, and checksum check instead of a postal pattern.
Frequently asked questions
How do I validate a ZIP code format for a selected country?
Select Country or region, enter the value in Postal/ZIP code, and read the result. The check uses that region's length and pattern rules.
Can a postal code validator guess the country?
No. You must select Country or region, and the tool checks that selection instead of inferring a country from the code.
Can I validate postal codes in bulk?
Yes. Choose Bulk Codes, select Country or region, and paste values into Postal/ZIP codes one per line or separated by commas.
Does postal code validation prove the code exists?
No. A Valid format result means the value matches the selected region's structure; it does not confirm assignment to a real address.
Are postal codes sent anywhere during validation?
The checks run in the browser. The page makes no request with submitted codes to a postal or mapping service.