Credit Card Number Validator
Check whether a card number is correctly formatted — Luhn checksum, length and card brand (Visa, Mastercard, Amex, Discover…). For testing forms; nothing is stored or sent.
How to use
- 1Type or paste a card number (spaces and dashes are fine).
- 2See the detected brand and whether it passes the Luhn check.
How it's calculated
The Luhn algorithm doubles every second digit from the right (subtracting 9 if over 9) and checks the total is divisible by 10. The brand comes from the leading digits (IIN) and length.
Frequently asked questions
Does a valid result mean the card is real?
No — it only means the number is well formed. Only the card issuer can say whether an account exists or has funds.
Is it safe to type a card number here?
The check runs entirely in your browser and nothing is sent or saved. Still, use test numbers such as 4111 1111 1111 1111 when testing.
What are test card numbers?
Payment providers publish numbers like 4242 4242 4242 4242 (Visa) and 5555 5555 5555 4444 (Mastercard) that pass Luhn but can't be charged.