Luhn Check (Card, IMEI)
Local ProcessingCheck numbers that use a Luhn check digit, such as card numbers and IMEIs.
How It Works & Processing Standards
Check numbers that use a Luhn check digit, such as card numbers and IMEIs.
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Current Limits
- Maximum input length: 100,000 characters
The Luhn algorithm doubles every second digit from the right, sums all digits and checks for a multiple of 10. Choose generic, card number or IMEI under "Task".
Only the check digit is computed; issuer, issuance and device registration are not checked. Do not enter real card numbers.
What You Can Do
- Luhn
- Checks a number of any length against Luhn.
- Card number
- Shows whether the check digit matches and what it should be.
- IMEI
- Checks the last digit of a 15-digit phone IMEI.
How to Use Luhn Check (Card, IMEI)
- 1Choose a taskLuhn, card number or IMEI.
- 2Enter the numberSpaces and hyphens are fine.
- 3Read the resultSee whether it is valid.
Examples
Luhn sample number
Input: 79927398713
Result: ✓ Valid — 11 digits
Test card number
Input: 4111 1111 1111 1111
Result: ✓ Check digit matches — computed check digit 1
IMEI
Input: 490154203237518
Result: ✓ Valid
Common Use Cases
- Checking test card numbers while building a payment form
- Making sure an IMEI was copied correctly before buying a used phone
Frequently Asked Questions (FAQ)
Does passing Luhn mean the card is real?
No. Luhn only catches typing mistakes; test numbers such as 4111 1111 1111 1111 pass too.