Credit Card Number Validator
Check a card number against the Luhn checksum and identify the issuer. Runs entirely in your browser: the number is never sent or stored.
Input
Result
The result appears here as you type.
What this tool is for
This checks the mathematics of a card number, nothing more. The Luhn algorithm catches mistyped digits, and the leading digits identify the issuer. It cannot tell you whether a card exists, has funds, or belongs to anyone, because that requires a payment network. Everything runs in your browser and no number is transmitted or kept.
How to use it
- Enter the card number, with or without spaces.
- Read the checksum verdict and the detected issuer.
- Use test numbers from your payment provider documentation when checking a form.
Frequently asked questions
Does a valid checksum mean the card works?
No. It means the digits are internally consistent. Whether the card is real, active or funded can only be answered by the issuer through a payment network.
Is it safe to enter a real card number?
The check runs locally and nothing leaves the page, but there is no reason to enter a real number. Test numbers published by Stripe, Adyen or your gateway are made for this.
How does the Luhn check work?
Every second digit from the right is doubled, digits above nine have nine subtracted, everything is summed, and a valid number leaves a total divisible by ten. It catches single digit typos and most transpositions.