Credit Card Validator

Our Credit Card Validator is a free online tool that verifies if a credit card number is valid through the Luhn Algorithm.

Besides validating the mathematical structure of the number, the tool also automatically identifies the card brand (Visa, Mastercard, American Express, Elo, or UnionPay).

It's ideal for developers who need to test payment systems, validate forms, or create automated tests without using real card data.

The Luhn Algorithm, also known as Modulo 10, is a verification method used to validate credit card numbers. It was created to detect accidental typing errors.

The algorithm works as follows:

1. Starting from the second-to-last digit and moving left, double the value of every second digit.
2. If the result of doubling is greater than 9 (e.g., 7×2 = 14), add the two digits of the result (1 + 4 = 5).
3. Add all the resulting digits, including those that were not doubled.
4. If the total is a multiple of 10 (i.e., the sum ends in 0), the number is considered valid.

This algorithm doesn't guarantee that the card exists or is active, only that the number was entered correctly.

Each credit card brand has specific patterns in the first digits of the number, known as BIN (Bank Identification Number). Our tool automatically identifies:

• Visa: Numbers starting with digit 4.
• Mastercard: Numbers starting with 51-55 or 2221-2720.
• American Express: Numbers starting with 34 or 37 (has 15 digits).
• Elo: Numbers starting with 4011, 4576, 5067, 6363, 5090, or 6278.
• UnionPay: Numbers starting with 62.

This tool is essential for various development and testing scenarios:

• Development Testing: Validate payment forms and input fields before integrating with real processors.
• Data Validation: Check if card numbers were entered correctly in systems and databases.
• Learning: Understand how the Luhn Algorithm works and the structure of credit card numbers.
• Automated Testing: Create unit and integration tests for payment processing systems.