Card Number Validator (Luhn)
Check whether a card number passes the Luhn checksum and see which network it belongs to. Useful for testing payment forms with test numbers.
Check whether a card number passes the Luhn checksum and see which network it belongs to. Useful for testing payment forms with test numbers.
Card numbers include a final check digit. The Luhn algorithm uses it to catch typing mistakes without contacting the bank. Payment forms often run this check before sending a number for authorisation.
This tool runs the Luhn check and identifies the card network from the number's prefix and length. It is meant for testing with test card numbers.
The Luhn algorithm, patented by Hans Peter Luhn at IBM in 1960 and now in the public domain, is a checksum designed to catch accidental typing errors. Starting from the rightmost digit, which is the check digit, move left and double every second digit. If doubling gives a number above nine, subtract nine. Add all the digits together, and the number passes if the total is divisible by ten. It detects any single digit error and most swaps of adjacent digits, though not every transposition, such as 09 and 90.
Passing this check means only that the digits are internally consistent. It does not confirm that the card exists, is active, has funds or belongs to anyone, and it cannot detect deliberate fraud, because anyone can compute a valid check digit. The network is guessed from the issuer identification number, the leading digits: Visa begins with 4, Mastercard with 51 to 55 or 2221 to 2720, American Express with 34 or 37. Only a payment processor can authorise a card. Use published test numbers from payment providers when you need sample data for development.
No. It only means the digits are consistent. It says nothing about whether an account exists or has funds.
No. Use test numbers such as the ones payment providers publish. Nothing is sent anywhere, but there is no reason to type a real number.
The prefix and length do not match one of the supported networks.
IMEI numbers and many national ID and account numbers.
No. It catches all single digit errors and most adjacent swaps, but some errors, including swapping 09 with 90, produce the same checksum and pass undetected.
No. It only shows the digits satisfy a formula. Whether a card is real, active, within limit and authorised can be decided only by the issuing bank through a payment processor.