Luhn Validator checks whether a number passes the Luhn checksum used by many card and identifier formats. It validates syntax only and does not verify account status.
Validate card-like numbers with the Luhn checksum algorithm. Everything runs locally in this tab.
Valid Luhn checksum
Yes. The tool is free and runs directly in your browser with no account required.
No. Processing happens locally in the browser tab. Your input is not sent to a server.
Catching typos in a manually entered card number, IMEI, or other Luhn-checked identifier before it's submitted or stored, by running the same checksum algorithm those systems use.
It's a simple checksum: starting from the rightmost digit, every second digit is doubled (subtracting 9 if the result exceeds 9), then all digits are summed. If the total is divisible by 10, the number passes.
No. It only means the digit sequence is mathematically self-consistent under the Luhn formula — the same property every real card number has, but so does an enormous number of numbers nobody issued. It says nothing about whether an account exists, is active, or belongs to anyone.
Credit and debit card numbers, IMEI numbers for mobile devices, Canadian Social Insurance Numbers, and several other identifier formats that include a Luhn check digit as their final digit.
Yes — non-digit characters are stripped before the checksum runs, so formats like '4242 4242 4242 4242' or '4242-4242-4242-4242' work the same as a plain digit string.
The algorithm requires at least two digits to compute a meaningful checksum; anything shorter is reported as invalid automatically.
