Runs locally
Luhn Check
Checksum for a card-like number. It does not contact a bank.
Ctrl+Enter runs. Ctrl+Shift+Backspace clears.
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Checksum for a card-like number. It does not contact a bank. Runs in the browser. Nothing is uploaded.
About this tool
Catch typos in card numbers, IMEIs and other identifiers that use the Luhn checksum. Paste the number and see whether the check digit is valid.
How to use it
- 01
Paste the number; spaces are allowed.
- 02
Read whether the Luhn check passes.
- 03
Correct the number if it fails.
FAQ
Frequently asked questions
Does a valid result mean the card works?
No. It only proves the digits are consistent; it says nothing about whether the card exists or has funds.
Is the number sent anywhere?
No. The check runs in your browser, and nothing is stored.