ZIP and Postal Code Validator

Free online ZIP and Postal Code Validator that runs directly in your browser.

Secure (SSL)

Client-Side Processing

100% Free

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Instructions

1

Enter data
Enter content, paste text or load a file from disk.
2

Click the button
The tool will immediately process your data in the browser.
3

Get the result
Copy the finished text or save the file to your device.

                                                function runTool() {

                                                  return "Result ready in 0.1s";

                                                }

Settings

Country

Input data

10 characters

Strict mode Tool Option

Normalize Tool Option

Notes

Result

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Other tools you may find useful

Postcode validator - 60+ countries, Poland, USA, UK, DE

The postcode is a key element of a postal address - different countries have different formats, lengths and rules. The tool validates the postal code format for over 60 countries: it checks the regex pattern, length and (optional) region affiliation.

postal code validator ZIP code check postal code PL format postal code validator

Postal code formats

Poland (PL): XX-XXX (5 digits with a dash, e.g. 00-001). USA ZIP: 12345 or 12345-6789 (ZIP+4). UK: AN NAA or ANN NAA (e.g. SW1A 1AA). Germany (DE): 5 digits (10115). France (FR): 5 digits (75001). Netherlands (NL): 1234 AB. Canada (CA): A1A 1A1. Australia (AU): 4 digits. Japan (JP): 123-4567.

Poland postal numbers - structure

First 2 digits: postal area (00-XX Warsaw, 30-XX Kraków, 60-XX Poznań, 80-XX Gdańsk). Format: XX-XXX where X=digit. Full regex: ^[0-9]{2}-[0-9]{3}$. Extended validation: checking whether the prefix corresponds to an existing city (optional database).

Extended vs format validation

Format (regex): only checks whether the string matches the format pattern. Fast, without a base. E.g. 99-999 will pass. Extended (database): checks whether the code actually exists in the postal database of a given country. Slower, requires an up-to-date database. For e-commerce: extended for key markets.

Form validation integration

HTML5:– native validation without JS. JavaScript: /^[0-9]{2}-[0-9]{3}$/.test(zip). Libraries: libaddressinput (Google), Zod (.string().regex()), Yup. Error message: "Zip code should be in the format XX-XXX (e.g. 00-001)."

FAQ

Why are postal codes important for e-commerce?

Invalid postal code = parcel not delivered + return cost. Validation before placing an order: saving logistics costs. UPS/DHL/InPost: check the zip code before accepting the shipment. For Poland: error 99-999 instead of 99-000 may direct you to the wrong post office.

How to check whether a postal code belongs to a city?

Poczta Polska: postal code database (paid license). Central Statistical Office TERYT: free database of administrative divisions. OpenStreetMap Nominatim API: geocoding (code → coordinates → city). Google Geocoding API: accurate verification (paid at higher traffic).

What is ZIP+4 Code (USA)?

ZIP: 5 digits (basic, e.g. 90210). ZIP+4: additional 4 digits after the dash (e.g. 90210-1234) – specifies the delivery sector (block, office). USPS uses ZIP+4 for automatic sorting. For standard orders: A 5-digit ZIP will suffice. USPS lookup: usps.com/zip-code-lookup.

Is UK postcode case-sensitive?

No – SW1A 1AA = sw1a 1aa = SW1A1AA. UK format: outward part (SW1A) + space + inward part (1AA). Regex: ^[A-Z]{1,2}[0-9][A-Z0-9]?\s*[0-9][A-Z]{2}$. There may be no space or one space. UK postcodes database: postcodes.io (free API).

How to validate postal codes in multiple countries at the same time?

google-libaddressinput library (Android/iOS/web): Contains rules for 200+ countries. Tools: addressr (Node.js), postcode-validator (npm). Simplest: if the country is unknown, validate only alphanumeric 3-10 characters without special characters.

Related tools: IBAN validator, JSON validator and XML validator.