How it works
How to use the Credit Card Validator
Enter a card number
Type or paste a value — results update instantly as you type.
Read the results
Every equivalent value is listed, with the most relevant one highlighted.
Copy what you need
Each result has its own copy button.
About the Credit Card Validator
Check whether a card number is well-formed: the Luhn checksum, the card network (Visa, Mastercard, Amex, Discover, JCB, Diners, UnionPay, Maestro) from its prefix, and the expected length. It cannot tell whether an account exists — and the number never leaves this page.
Built for developers
Why developers use it
Private by design
Runs 100% in your browser. Nothing you paste is uploaded, logged or stored on a server.
Instant results
Output updates as you type, with precise error locations when something is wrong.
Works offline
Once loaded, the tool keeps working without a connection. Install it as an app if you like.
Free, no sign-up
No accounts, no limits, no watermarks.
FAQ
Frequently asked questions
Is my data uploaded anywhere?
No. Everything runs locally in your browser — nothing you type, paste or open is sent to a server, logged or stored. The tool keeps working offline once the page has loaded.
Keep going
Related tools
- JWT DecoderDecode JWTs, inspect claims and verify signatures
- UUID GeneratorGenerate UUID v4 / v7 in bulk and inspect UUIDs
- Regex TesterTest JavaScript regular expressions with live highlighting
- Timestamp ConverterConvert Unix timestamps to dates and back, in any time zone
- Cron Expression ExplainerExplain crontab schedules and show next run times
- Text & File DiffCompare two texts or files line by line
- Test Credit Card Number GeneratorGenerate Luhn-valid test card numbers
- JSON ValidatorFind and fix JSON syntax errors