IMEI Calculator – Check Digit & Luhn Validator
Use this IMEI calculator to find the last digit from a 14-digit body, or to check a 15-digit IMEI with the Luhn checksum. The calculation runs in your browser and does not verify device identity or status.
Enter 14 or 15 digits. Spaces, Unicode separators and hyphens are removed before validation.
Calculate the 15th digit: worked example
For the 14-digit body 12345678901234, the Luhn sum is 63. The next multiple of 10 is 70, so the check digit is 7. The complete number is 123456789012347.
These synthetic examples demonstrate checksum arithmetic only. They do not identify a device.
Enter one 14- or 15-digit value per line, or separate values with commas. Maximum 500.
Understanding IMEI structure
A 15-digit IMEI-shaped value can be split into a TAC, serial section and Luhn check digit
TAC (Type Allocation Code)
The first 8 digits form the TAC. Model attribution requires current licensed data; this validator does not perform a TAC-to-device lookup.
Serial Number
Digits 9–14 form the serial section. This tool can parse it but cannot verify assignment or uniqueness.
Check Digit
The final digit is calculated with Luhn for error detection. A matching checksum proves mathematical structure only.
What this validator does not check
Format and Luhn are local arithmetic checks, not a device or network lookup
What is a TAC?
The Type Allocation Code is the first eight IMEI digits. Reliable model attribution requires current licensed registry data. This page extracts the TAC but does not map it to a device.
Bulk structural check
Check up to 500 values. Fourteen-digit bodies are completed separately; 15-digit values receive a format and Luhn result. CSV and JSON exports preserve that distinction.
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IMEI calculator FAQ
Common questions about the last digit, check digit and Luhn checksum
How do I validate an IMEI number?
Enter a 14-digit body or a complete 15-digit IMEI. The tool calculates or checks the Luhn digit and displays the TAC, serial section and check digit.
What is the Luhn algorithm?
The Luhn algorithm (also called modulus 10 or mod 10 algorithm) is a checksum formula used to validate identification numbers like IMEIs. It detects common errors in number entry by performing mathematical calculations on each digit.
What is a TAC in an IMEI?
TAC stands for Type Allocation Code and forms the first eight IMEI digits. This validator extracts the TAC but does not map it to a model; reliable attribution requires current licensed data.
Is IMEI validation accurate?
IMEI validation checks if a number follows the correct format and passes the Luhn algorithm. However, a valid IMEI format does not guarantee the device exists or is not blacklisted. For device status, contact your carrier.
What are the parts of an IMEI?
An IMEI has an eight-digit TAC, a six-digit serial section and a Luhn check digit. Parsing those parts or passing Luhn does not verify assignment, ownership, device status or uniqueness.
Can I check multiple IMEIs at once?
Yes. The bulk tab checks format and Luhn for up to 500 values and exports CSV or JSON. A passing result remains a structural check, not device verification.
Does this validator identify the device or check its status?
No. It does not query GSMA, carriers, manufacturers, blocklists, warranty systems or ownership records. A format and Luhn pass is only a structural result.
What is an IMEI calculator?
An IMEI calculator works out the last digit from the first 14 digits with the Luhn checksum. Paste a 14-digit body to get that check digit, or paste a full 15-digit IMEI to see whether the last digit already matches.
How do I calculate the last digit of an IMEI?
Enter the first 14 digits. The calculator doubles every second digit, sums the result and sets the last digit so the total is a multiple of 10. That last digit is the Luhn check digit. It confirms the number's structure only, not a real device.