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Credit Card Validator

Enter a credit card number to validate it using the Luhn algorithm and display card brand and detailed information.

The card number will be validated in real-time as you type

How to use

About this tool

Validates card numbers with the Luhn algorithm and infers brand (Visa, Mastercard, etc.). No real payment processing.

How to use

Enter a number (with or without dashes/spaces); view validation and inferred brand.

Use cases

• Client-side form validation • Testing with known numbers • Learning Luhn

Privacy and data

Validation is in-browser; card numbers are not sent to a server. Do not enter real card numbers.

FAQ

Q: What is the Luhn algorithm?
A: The Luhn algorithm (Luhn formula) is a checksum formula used to validate credit card numbers. It doubles alternate digits from right, sums all digits, and checks divisibility by 10. A valid card number passes this check — but it does not verify the card actually exists or has funds.
Q: Which card brands can be detected?
A: Visa, Mastercard, American Express, Discover, JCB, Diners Club, UnionPay, and others are detected by their IIN (Issuer Identification Number) prefix patterns.
Q: Can I use this with test card numbers?
A: Yes. Standard test numbers like 4111 1111 1111 1111 (Visa) or 5500 0000 0000 0004 (Mastercard) will validate correctly and are safe to enter since they are publicly known test data.
Q: Should I enter my real card number?
A: No. The tool is intended for development and testing only. Although processing is in-browser, as a security habit never enter real card numbers into any third-party tool.
Q: Does this tool send card numbers to a server?
A: No. All validation is performed entirely in the browser. Card numbers are never sent to any server.