Test the 'check-sum digit' of Any Credit or Debit Card

The last digit of a credit card number is assigned to the credit card number, based on the values of the preceeding digits in the credit card number.

Enter the entire card number in the "Luhn test" field below.

Credit Card Number: 


The data entered into these fields are not stored or viewed, and will be erased upon reset or leaving the page.

Make sure you enter the PAN number correctly. PAN errors entered into the Luhn test field can return false positives and false negatives.

The Luhn Test

The Luhn algorithm generates the last digit (check-sum digit) of the credit or debit card number - the primary account number (PAN). The entire card number (PAN) should be entered to check if the number is a possible credit card or debit card. The checker cannot confirm that the credit card is valid. However, the checker will test if the sequence of numbers is not valid and therefore the card is invalid.

A check-sum digit is used frequently in other numbering systems to ensure that numbers are correctly formed and have not succumb to a transcribing error, or a basic fraud attempt.

Here is a list of other number systems that have check-sum digits calculated using the Luhn algorithm.

  • Greek Social Security Numbers (ΑΜΚΑ)
  • Canadian Social Insurance Numbers
  • Credit card numbers
  • National Provider Identification Number in US
  • Israel ID Numbers
  • IMEI numbers (International Mobile Equipment Identity)

Read more about the Luhn algorithm HERE.