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Luhn Mod N Calculator

Reviewed by Calculator Editorial Team

The Luhn Mod N Calculator helps verify and generate check digits using the Luhn algorithm with a custom modulus. This tool is essential for validating identification numbers, credit card numbers, and other codes that require checksum validation.

What is Luhn Mod N?

The Luhn algorithm, also known as the "modulus 10" algorithm, is a simple checksum formula used to validate identification numbers. The Luhn Mod N calculator extends this concept to allow validation with any modulus (N), not just 10.

This algorithm is widely used in:

  • Credit card numbers
  • Identification numbers
  • Barcode validation
  • Check digit generation

Note: The standard Luhn algorithm uses modulus 10, but the Luhn Mod N calculator allows you to specify any modulus for more flexible validation.

How to Use the Calculator

Using the Luhn Mod N Calculator is straightforward:

  1. Enter the number you want to validate or generate a check digit for in the "Input Number" field.
  2. Specify the modulus (N) you want to use in the "Modulus" field.
  3. Click the "Calculate" button to perform the validation or check digit generation.
  4. Review the result, which will indicate whether the number is valid or provide the generated check digit.

The calculator will display the result and explain whether the input number is valid according to the Luhn Mod N algorithm.

Formula

The Luhn Mod N algorithm works as follows:

1. Starting from the rightmost digit (the check digit) and moving left, double the value of every second digit.

2. If doubling a digit results in a number greater than 9, add the digits of the product (or subtract 9 from the product).

3. Sum all the digits.

4. The number is valid if the sum modulo N equals 0.

For check digit generation, the algorithm is applied to the number without the check digit, and the check digit is calculated to make the total sum modulo N equal to 0.

Worked Example

Let's validate the number 79927398713 with modulus 10:

  1. Starting from the right, double every second digit: 7, 18, 9, 18, 7, 6, 9, 16, 7, 6, 3
  2. Sum the digits of numbers greater than 9: 7, (1+8), 9, (1+8), 7, 6, 9, (1+6), 7, 6, 3
  3. Calculate the sum: 7 + 9 + 9 + 9 + 7 + 6 + 9 + 7 + 7 + 6 + 3 = 70
  4. 70 modulo 10 equals 0, so the number is valid.

This example shows how the Luhn Mod N algorithm works to validate a number.

Applications

The Luhn Mod N algorithm is used in various applications, including:

  • Credit card validation
  • Identification number verification
  • Barcode validation
  • Check digit generation for codes

By using the Luhn Mod N Calculator, you can easily validate or generate check digits for these applications.

FAQ

What is the difference between Luhn Mod N and standard Luhn algorithm?

The standard Luhn algorithm uses modulus 10, while Luhn Mod N allows you to specify any modulus for more flexible validation.

How do I generate a check digit using this calculator?

Enter the number without the check digit, specify the modulus, and the calculator will generate the check digit needed to make the number valid.

Can I use this calculator for credit card numbers?

Yes, you can use the Luhn Mod N Calculator to validate credit card numbers by setting the modulus to 10.

What if the number I enter is invalid?

The calculator will indicate that the number is invalid and suggest the correct check digit if needed.