Card Validator & Generator

Validate card structures via the Luhn algorithm and generate mock data for testing.

Whenever possible, your data never leaves your device. Your security is our priority.

Luhn Validator

Card Number

Test Data Generator

Select Network

About this Tool

Credit card validation relies on the Luhn Algorithm (Modulus 10), a mathematical checksum formula created by IBM scientist Hans Peter Luhn in 1954. It is designed to protect against accidental errors, like mistyping a digit.

The tool identifies the card's network (Visa, Mastercard, Amex, etc.) based on its Issuer Identification Number (IIN) prefix, and then runs the Luhn checksum to verify if the number is structurally valid.

Developer Disclaimer: The generator creates dummy test numbers that pass the Luhn check for testing payment gateways (like Stripe test mode). These are not real credit cards, do not have CVVs or expiration dates, and cannot be used for actual transactions.

How to Use

Validate a Number

Type or paste a card number into the Validator. It will instantly strip spaces and dashes, identify the network, and run the mathematical checksum.

Generate Test Data

Select a card network from the dropdown and click Generate. The tool will calculate a structurally valid fake number using reverse Luhn logic.

Copy or Reset

Use the copy button to instantly grab the generated test number, or use the clear actions to wipe the outputs and start fresh.

Frequently Asked Questions

Yes, because this application runs entirely locally in your browser. However, as a general cybersecurity best practice, you should never type your real credit card number into random online forms unless making a purchase.

The Luhn algorithm only checks if the number is mathematically possible and free of typos. It does not ping a bank to check if the account actually exists, is active, or has funds.

Different networks have different standards. Visa and Mastercard standardly use 16 digits, American Express uses 15, and legacy Diners Club cards often used 14.