Luhn Algorithm or Modulus 10 Calculator

This online tool will calculate/validate the luhn digit number for any cards.

  

Results...

Initial number:

7
9
9
2
7
3
9
8
7
1
0

Step1 : Starting with the second-to-last digit and moving to the left, double every second digit:

7
18
9
4
7
6
9
16
7
2
0

Step2 :If the result of the doubling is a two-digit number, add those 2 digits together:

7
1+8
9
4
7
6
9
1+6
7
2
0

Step3 :Now take the sum of all the digits:

7
9
9
4
7
6
9
7
7
2
0

Sum = (7 + 9 + 9 + 4 + 7 + 6 + 9 + 7 + 7 + 2 + 0) = 67


67 mod 10 =

1, that means this number is Not Valid.


Info: If you change the last digit from 0 to 3, the sum will be 70, and the number will be valid.

What is Luhn-Algorithm

The Luhn algorithm or Luhn formula is also known as modulus 10 (or) mod 10 algorithm.

This formula used to validate a variety of identification numbers.

Example :

Credit card numbers

Social Security Numbers (SSNs).

IMEI numbers

National Provider Identifier numbers

Steps to calculate the luhn check digit:

Step 1) From the rightmost digit, which is the check digit, moving left, double the value of every second digit;

Step 2) If the product of this doubling operation is greater than 9, then sum the digits of the products or alternatively subtract 9 from the product.

Step 3) Take the sum of all the digits.

Step 4) Sum value Mod 10.

Step 5) Result = 1 , that means this number is Not Valid.

         Result = 0 , that means this number is Valid.