IMEI Number Meaning: What Those 15 Digits Tell You
An IMEI is not random. Every digit encodes something, from the model and brand to a built-in typo detector. Here is the full breakdown.
The Three Parts of an IMEI
If you have read our What is IMEI? guide, you know the 15-digit number is structured into three sections. This article goes one level deeper and explains what each section actually reveals about your phone.
The 15 digits are divided as follows:
| Section | Digits | Name | Meaning |
|---|---|---|---|
| 1 | 1-8 | TAC | Brand, model, capacity, color |
| 2 | 9-14 | SNR | Device serial number |
| 3 | 15 | Check digit | Luhn validation |
The TAC Code: Digits 1-8
The Type Allocation Code (TAC) is the most informative part of the IMEI. The first 8 digits identify the exact device model, and within the TAC the first 2 digits are the Reporting Body Identifier β the GSMA-accredited agency that issued the TAC.
Reporting body identifiers
| Code | Agency | Country/Region |
|---|---|---|
| 01 | CTIA | United States |
| 35 | BABT | United Kingdom |
| 86 | TAF | China |
| 99 | Global DSMA | Multiple |
Note that the reporting body identifies where the TAC was registered, not where the phone was manufactured. A Samsung phone assembled in Vietnam can still carry a 35 (UK BABT) TAC if Samsung registered the model through BABT.
What the TAC reveals
Looking up the TAC in the GSMA database returns:
- Brand (Apple, Samsung, Xiaomi, etc.)
- Exact model (e.g., iPhone 15 Pro Max, Galaxy S25 Ultra)
- Storage capacity (128GB, 256GB, 512GB, 1TB)
- Color (on some models)
This is the backbone of any IMEI check. If the TAC says the device is a 128GB black iPhone 14 but the seller claims it is a 1TB iPhone 15 Pro, you know immediately it is a scam or a clone.
For comparison, CDMA networks use MEID instead of IMEI β see our guide on what MEID is if you are dealing with an older device.
The SNR: Digits 9-14
The Serial Number Range (SNR) is a 6-digit number assigned by the manufacturer to differentiate individual devices that share the same TAC. Every iPhone 15 Pro Max has the same TAC, but each unit gets a unique SNR on the assembly line.
The SNR alone is not very useful to consumers β it does not encode a readable meaning. But combined with the TAC it forms the unique identifier carriers and manufacturers use to track warranty activation and blacklist status for that specific physical device.
If you are verifying an Apple device, the manufacturer-assigned serial number typically returns richer information (activation date, purchase country, AppleCare+ status) than the IMEI SNR.
The Check Digit: Digit 15
The 15th digit is a check digit calculated from the first 14 digits using the Luhn algorithm. Its only purpose is validation: if you mistype a single digit when entering an IMEI, the check digit will not match and the lookup will be rejected instantly, without wasting a database query.
How to calculate the IMEI check digit
Here is the Luhn algorithm step by step, using IMEI 35238091234567? as an example (where ? is the unknown check digit):
- Write down the first 14 digits: 3 5 2 3 8 0 9 1 2 3 4 5 6 7
- Starting from the rightmost digit, double every second digit: the positions to double are 7, 5, 3, 1 (counting from the right of the 14 digits)
- If a doubled value is 10 or more, sum its own digits (e.g., 14 becomes 1+4=5)
- Sum all the resulting digits (doubled and undoubled)
- The check digit is the number that makes the total a multiple of 10
If the sum of step 4 is 53, the check digit is 7 (because 53 + 7 = 60, which is a multiple of 10). That is why the example IMEI ends in 8 only if the math works out to 52. IMEICheck and every other IMEI tool uses this exact check before querying any backend database.
Try it yourself: Enter any IMEI into our checker. If you change a single digit, the tool immediately says "invalid IMEI" β that is the Luhn check in action, before any network call.
IMEI vs IMEISV
You may occasionally see a 16-digit number labeled IMEISV (International Mobile Equipment Identity - Software Version). IMEISV replaces the check digit with a 2-digit software version number. It is used internally by carriers and is rarely shown to consumers. Every mainstream smartphone uses the 15-digit IMEI, not IMEISV.
What an IMEI Can and Cannot Tell You
| Can tell you | Cannot tell you |
|---|---|
| Brand and model | Owner name or phone number |
| Storage and color (sometimes) | GPS location of the phone |
| Warranty and activation date | Personal data, photos, messages |
| Carrier lock and blacklist status | Apps installed or screen lock PIN |
An IMEI is a device identifier, not a tracking beacon. It carries no personal data about the owner.
Frequently Asked Questions
What does the first digit of IMEI mean?
The first two digits of an IMEI form the Reporting Body Identifier, which identifies the GSMA-accredited agency that allocated the TAC code. For example, 01 indicates the CTIA (United States), 35 indicates the BABT (United Kingdom), and 86 indicates the TAF (China). The first digit alone does not encode a meaning on its own; it must be read together with the second digit.
What can the TAC code tell you?
The TAC (Type Allocation Code), the first 8 digits of the IMEI, identifies the exact device model, brand, and sometimes the storage capacity and color. By looking up the TAC in the GSMA database you can confirm whether a phone is genuinely the model the seller claims. A mismatch between the TAC-identified model and the physical device is a strong indicator of a cloned or counterfeit phone.
How is the IMEI check digit calculated?
The 15th IMEI digit is calculated using the Luhn algorithm. Double every second digit from the right of the first 14 digits, sum the individual digits of those doubled values, add the remaining undoubled digits, and the check digit is the number that makes the total a multiple of 10. This lets IMEI checkers instantly reject typos without calling any database.
Do all phones have the same IMEI format?
All GSM, LTE, and 5G phones use the 15-digit IMEI format. Older CDMA phones use a 14-digit MEID instead. Some satellite phones and IoT devices use the 16-digit IMEISV format (which replaces the check digit with a software version). But every mainstream smartphone you can buy today uses the standard 15-digit IMEI.
Conclusion
The 15 digits of an IMEI are a compact package of device intelligence: the TAC reveals the brand and model, the SNR differentiates your physical unit from every other of the same model, and the Luhn check digit guarantees the number is typed correctly. Knowing this structure helps you understand exactly what an IMEI check can and cannot tell you, and makes it much harder for a seller to fool you with a fake model.