The Credit Card Validator Tool is an online utility crafted for testers to verify if a provided credit card number is valid according to the selected card type. This tool offers a quick and straightforward way for QA professionals to check if an inputted credit card number meets the structural requirements for major card types like Visa, MasterCard, and American Express, among others.

Key Functionalities

• Luhn Algorithm Validation: This algorithm ensures the number isn’t just structurally correct but also mathematically valid for real-world usage, catching input errors quickly.

• Format and Length Verification: In addition to card-specific patterns, the validator checks for numeric-only input and confirms the length based on the selected card type. This prevents users from submitting inputs that don’t meet basic formatting rules, further ensuring accurate testing.

How to verify the card number using Luhn's algorithm?

Luhn's algorithm is used to generate and verify the check digit in the card number. The verification process has the following steps:

• Double the alternative digits from the right. If the value is greater than 9 then take the sum of digits in the value. Eg: Card Number 4376 9909 7878 9659

  • Setp 1 - 4 |3 |7 |6 |9 |9 |0 |9 |7 |8 |7 |8 |9 |6 |5 |9

  • Setp 2 - 8 |3 |14 |6 |18 |9 |0 |9 |14 |8 |14 |8 |18 |6 |10 |9

  • Setp 3 - Sum ( 8 |3 |5 |6 |9 |9 |0 |9 |5 |8 |5 |8 |9 |6 |1 |9 ) = 100

• Sum all digits generated in the step 3 and take the modulo 10 of the sum.

• If the modulo 10 is 0 then the card number could be a valid number.

Major credit card issuers