IMEI Calculator — Validate Any Mobile IMEI Number Instantly
The International Mobile Equipment Identity (IMEI) is a unique 15-digit number that identifies every mobile phone and many tablets worldwide. Our free IMEI calculator lets you enter a 15-digit IMEI and instantly validate it using the Luhn checksum algorithm, the same standard the GSMA uses to ensure IMEI numbers are well-formed. The tool also extracts the first eight digits, the Type Allocation Code (TAC), which identifies the manufacturer and model of the device, and confirms the final checksum digit. Whether you are checking a phone before purchase, verifying a second-hand device, or confirming the IMEI printed on a box or in device settings matches what the device reports, this validator gives you a quick, reliable integrity check. Enter your 15-digit IMEI above to validate it.
What an IMEI Number Tells You
An IMEI is structured into three parts. The first eight digits form the Type Allocation Code (TAC), which identifies the manufacturer and the model of the device. The next six digits are the serial number assigned by the manufacturer to that specific unit. The final digit is the checksum, calculated using the Luhn algorithm from the preceding 14 digits, which allows quick detection of transcription errors or fake numbers. By extracting the TAC, you can look up the brand and model of the device against GSMA databases, useful when verifying that a phone matches the IMEI on the box or in the device settings. A mismatch between the model the seller claims and the model the TAC resolves to is a red flag for counterfeit or mislabeled devices.
The Luhn Checksum Explained
The Luhn algorithm is a simple but effective checksum formula used to validate a wide range of identification numbers, including credit cards and IMEIs. To validate a 15-digit IMEI, the algorithm processes the digits from left to right, doubling every second digit. If doubling produces a number greater than nine, its digits are summed (or equivalently, nine is subtracted). All the resulting digits are summed, and the total must be divisible by 10 for the IMEI to be valid. This catches single-digit errors and most adjacent transpositions, the two most common mistakes when an IMEI is copied or typed manually. The calculator performs this check automatically and reports whether the IMEI passes, along with the extracted TAC and the checksum digit, so you can confirm the structure of the number at a glance.
Why IMEI Validation Matters
Checking a phone IMEI before purchase protects you from several risks. A valid IMEI that matches the model the seller claims increases confidence that the device is genuine. An invalid IMEI, one that fails the Luhn check, almost always indicates a mistyped number or a counterfeit device, and is a reason to walk away. Beyond validation, the IMEI is the key identifier carriers and authorities use to block stolen or lost phones from network access, so confirming the IMEI of a second-hand phone against national blocklists (where available) before buying can prevent you from purchasing a device that will never connect to a network. In Pakistan, mobile phones are also registered with the PTA DIRBS system against their IMEI, so a valid IMEI that is properly registered is essential for the phone to work on local networks.
How to Find Your IMEI
There are several easy ways to find the IMEI of a phone. On most devices, dialing the universal short code for IMEI display shows the number on screen immediately with no menu navigation needed. The IMEI is also printed on the original packaging and, for many phones, on a small label under the battery or on the SIM tray. In the device settings, the IMEI appears under About Phone or General then About. When buying a used phone, compare the IMEI shown on screen with the one printed on the box and the one in the settings, as all three should match. A mismatch between these sources can indicate a refurbished, repackaged, or tampered device. Enter any of these IMEIs into the validator above to confirm its integrity in seconds.
Frequently Asked Questions
Does the validator tell me if a phone is stolen? No, it only checks the IMEI structure with the Luhn algorithm. To check a stolen or blocked status, use the IMEI blocklist service of your country (such as PTA DIRBS in Pakistan) with the IMEI.
Can a valid IMEI still be fake? A valid Luhn checksum confirms the number is well-formed, not that it is a real registered device. Cross-check the TAC against a GSMA database and the IMEI against a blocklist for full verification.
What if my phone has two IMEIs? Dual-SIM phones have two IMEIs, one per SIM slot. Both should validate. Enter them one at a time into the calculator to check each.
Bookmark this IMEI calculator to validate any device IMEI before purchase and to extract the TAC for model verification.
