HesapHanem

IMEI Validator

Check whether a phone's IMEI number is valid.

How it is calculated

An IMEI is 15 digits, and the last one is a check digit computed with the Luhn algorithm. Starting from the left, every second digit (positions 2, 4, … 14) is doubled, and if the doubled value is above 9, 9 is subtracted. All 15 resulting digits are added up. The number is valid when the total is divisible by 10: sum mod 10 = 0. The tool also shows the check digit the first 14 digits should have: (10 − (sum of first 14 mod 10)) mod 10. Spaces and dashes are ignored, but anything other than exactly 15 digits gives no result. A valid checksum does not prove the phone exists or is not blacklisted.

Worked example

Take 490154203237518. Double the digits in even positions: 9→18→9, 1→2, 4→8, 0→0, 2→4, 7→14→5, 1→2; these add up to 30. The digits in odd positions (4, 0, 5, 2, 3, 3, 5, 8) add up to 30. Total 60, divisible by 10, so the IMEI is valid. For the first 14 digits the sum is 22, so the expected check digit is (10 − 2) mod 10 = 8, which matches the last digit.

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Common mistakes

  • Entering a 16-digit IMEISV (which adds two software digits) or only the 14-digit TAC and serial part. Only 15 digits work.
  • Typing the IMEI of the SIM or the ICCID instead of the phone's own IMEI. They are different numbers.
  • Reading Valid as a guarantee that the phone is genuine, unstolen or unlocked. It only confirms the checksum.
  • Mistyping a single digit and assuming the phone is fake. Compare with the number printed under the battery or shown by dialling *#06#.

About this calculator

This tool checks whether a 15-digit IMEI (International Mobile Equipment Identity) is structurally valid using the Luhn algorithm — the same checksum used for credit card numbers. It doubles every second digit from the right, sums all digit values (subtracting 9 from any result over 9), and checks that the total is a multiple of 10; it can also compute the correct 15th check digit from the first 14.

Phone repair technicians, resellers, and mobile network staff use it to spot a mistyped or fake IMEI before registering a device, blacklisting a stolen phone, or entering it into inventory.

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Comments (1)

  • Editorial team

    A pass here only means the 15 digits satisfy the Luhn checksum. It does not show that the phone exists, belongs to the seller, or is free of a block or blacklist; those need a lookup by the operator or a national register. The tool also expects exactly 15 digits, so a 16-digit IMEISV is not accepted. If you get an invalid result, compare the digit it expects as the last one with yours: did you mistype it?

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