Example
Valid (Visa)
Credit Card Number Validator
Check if a credit card number is valid using the Luhn algorithm and detect its issuer instantly in your browser. Free online card number validator — no storage.
Enter the values below, then press Calculate (or press Enter). The calculator updates your results instantly. Try different values to see how your inputs change the outcome.
- Card number — enter a text value. A typical Card number would be e.g. 4242 4242 4242 4242.
- Review your results — the key output is highlighted, with supporting figures below.
Loading calculator…
Results
Result
| Detail | Value |
|---|---|
| Issuer | |
| Length (digits) |
What is this calculator for?
Validate a card number’s checksum (Luhn) and identify its most likely issuer.
How to Use This Calculator
Enter the values below, then press Calculate (or press Enter). The calculator updates your results instantly. Try different values to see how your inputs change the outcome.
- Card number — enter a text value. A typical Card number would be e.g. 4242 4242 4242 4242.
- Review your results — the key output is highlighted, with supporting figures below.
What You'll Need
- Card number
- a text value · required
About This Calculator
This validator runs the Luhn checksum algorithm, which detects any single mistyped digit or most transpositions, and cross-checks the leading digits to guess the brand (Visa, Mastercard, Amex, etc).
It does not check the balance, expiry, or whether the card exists — Luhn only confirms the number is mathematically well-formed. Everything runs locally; nothing is stored or transmitted.
Worked Examples
Frequently Asked Questions
Does valid mean the card can actually be used?
No. Luhn validity only means the digits pass the checksum. The tool cannot tell if funds exist or if the card is active — test with your own test cards only.
Which brands are detected?
Visa, Mastercard, American Express, Discover, and JCB by their leading digit ranges. Unknown prefixes are reported as "Unknown" even if the Luhn check passes.