Security & Password

Luhn Checksum Validator

Check card, IMEI and other numbers with the Luhn (mod 10) algorithm.

Security & Password

Local only

Numbers (one per line)

Everything stays in your browser

Your text is processed on your device — nothing is uploaded to a server.

How it works

Applies the Luhn mod-10 check and detects common card brands by prefix. Runs locally.

Good to know

How do I use it?

Enter your numbers (one per line) and press “Check”. Check the result, then copy or download it.

How does it work?

Applies the Luhn mod-10 check and detects common card brands by prefix. Runs locally.

Is my data uploaded?

No. Everything is processed in your browser and nothing is sent to a server. No account is needed.