ToolWren › Luhn Check

Credit Card & Luhn Validator

Validate a card or ID number against the Luhn checksum and detect the likely card type.

100% client-side · nothing is uploaded

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How to use the Luhn Check

Type or paste your text into the Input box.
The converted result appears automatically in the output area — no button to press.
Review the output, then click Copy to copy it to your clipboard.
Edit the input at any time and the result updates live.

Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.

About Luhn Check

What is the Luhn check

The Luhn algorithm is a checksum formula that catches accidental errors in numbers like credit cards, IMEIs and some IDs.

What it tells you

It reports whether the number passes the check, how many digits it has, and the likely card brand from its prefix.

Not a fraud check

Passing Luhn means the number is well-formed, not that it's a real, active card. It validates format only.

Frequently asked questions

Does passing Luhn mean a card is real?

No — it only confirms the number is well-formed, not that it exists or is active.

What uses the Luhn algorithm?

Credit/debit cards, IMEI numbers and some national IDs.

Is my number uploaded?

No — the check runs entirely in your browser.