Validate your Credit Card

Learn in few easy steps how the Luhn’s formula is applied and used to verify the last digit of the card (commonly known as the check digit) with the following credit card validator tool.

Luhn's Proof

Let us illustrate how we validate a credit card using Luhn’s formula with an interactive example.

We have noticed that you have not tried to validate any credit card number yet. We’ll demonstrate the entire process using a test number, 4929717681432141 and applying the Luhn’s formula.

The check digit is obtained by computing the sum of digits then computing 9 times that value modulo 10 (so that's: (79 * 9 mod 10)). In summary:

1. Compute the sum of the digits (79).
2. Multiply by 9 (711).
3. Take the last digit (1).
4. The result is your check digit.

Significance of First Digit

Many people do not know this as a fact that the left most digit of the card is very important. In the table below, we have outlined the meaning of this number in principal.

Credit Card Break Down by Issuer

Credit card companies generate their list of card numbers as per a pre- allotted set of pre-fixes. These pre- fixes are much like area codes of a phone number where the first 3 digits of a phone number tell you the area code of that state or province. Similar concept is used in credit card pre-fix numbers.