Validate credit card / IMEI numbers with the Luhn algorithm and compute the check digit. Luhn Validator & Check Digit is a free online tool from the ToolsRift Hash & Crypto Tools collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
A simple checksum (mod 10) formula that validates identification numbers such as credit cards, IMEI numbers, and some national IDs. It catches most single-digit typos and adjacent transpositions.
No — Luhn only verifies the check digit is consistent. It does not mean the card exists or is active. No data is sent anywhere; validation runs entirely in your browser.
Enter the number without its last digit and the tool appends the digit that makes the full number pass the Luhn check.