SECURITY TOOL
Credit Card Number Validator
Check a card number against the Luhn checksum and detect its card type.
Result
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Detected card type
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About this tool
Check whether a credit or debit card number passes the Luhn checksum algorithm used by all major card networks to catch typos and mistyped numbers. This only validates the number's mathematical structure — it does not check whether a card actually exists, is active, or has funds. Nothing is sent anywhere; the check runs entirely in your browser.
Frequently asked questions
- What is the Luhn algorithm?
- A simple checksum formula: starting from the rightmost digit, every second digit is doubled (subtracting 9 if the result exceeds 9), then all digits are summed. If the total is a multiple of 10, the number passes.
- Does passing this check mean the card is real or active?
- No — Luhn validation only confirms the number is internally consistent, the same check a form might do before even contacting a payment processor. It cannot confirm the card exists, is unexpired, or has any balance.
- Is my card number sent anywhere?
- No — the entire calculation happens locally in your browser using plain JavaScript; nothing is transmitted or stored.