Credit Card Check

Description

This check uses the LUHN Formula (Mod 10) to validate credit card (CC) numbers.

Validation Steps

1. Double every second digit from right to left (RTL).
2. Add each individual digit to get the sum.
3. If the sum modulo 10 is equal to 0, then the number is valid.

Validation Steps Example

1. To validate the CC: 371449635398431

   CC #	3	7	1	4	4	9	6	3	5	3	9	8	4	3	1
   Double every 2nd number (RTL)		x2		x2		x2		x2		x2		x2		x2
   Result	3	14	1	8	4	18	6	6	5	6	9	16	4	6	1

2. 3 + 1+4 + 1 + 8 + 4 + 1+8 + 6 + 6 + 5 + 6 + 9 + 1+6 + 4 + 6 + 1 = 80
3. 80 mod 10 = 0; Card number is valid.

Credit Card Input

Note: A green shadow means the credit card number passed the check. Red = failure.