What is it?
The Card Number Checker tests a card number with the Luhn checksum and shows its network. It runs only in your browser.
Who is it for?
Online shop owners testing checkout forms, developers testing card validation, and customers checking they typed a card number correctly before a payment fails.
How to use it
- Type or paste the card number in Card numbers (one per line). Spaces are fine, and you can check several numbers, one per line.
- Read the result for each line: valid or not, and the card network (Visa, Mastercard, RuPay…).
- Never type the CVV, expiry date or OTP: the tool does not need them.
“Not a valid number”
- Checksum fails: a digit is mistyped, or two digits are swapped. Compare it with the card again.
- Wrong length: Visa and Mastercard have 16 digits, Amex 15. A missing or extra digit fails.
What it cannot tell you
It does not know if a card is real, active, blocked or has money. A number can pass the check and still not exist.
Stay safe
- Never share your CVV, expiry date, PIN or OTP with anyone, including people who say they are from your bank.
- You never need to enter those here: the tool asks only for the number.
How the Luhn check works (worked example)
For 4111 1111 1111 1111: starting from the right, double every second digit (1 becomes 2, and 4 becomes 8). If doubling gives more than 9, subtract 9. Add all the digits: the total is 30, which ends in 0, so the number passes.
Card networks by first digits
- 4: Visa. 51–55 or 2221–2720: Mastercard. 34 or 37: American Express. 60, 65, 81, 82 and 508: often RuPay. 62: UnionPay. 35: JCB.
Fraud warning
Scammers sometimes ask people to “verify” a card on a website or by call. Your bank never needs your full number, CVV, expiry or OTP over the phone. If someone asks, hang up and call the number on the back of your card.
Tool: Card Number Checker
Still stuck?
Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.
Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.