IMEI vs MEID vs ESN: Which Number Does Your Phone Have?
Hexadecimal characters, fourteen digits, "bad ESN" — the legacy CDMA vocabulary, decoded.
| Identifier | Format | Where it came from | Use it today? |
|---|---|---|---|
| IMEI | 15 decimal digits | The GSM/UMTS/LTE/5G world — now effectively universal | Yes — this is the number every check uses |
| MEID | 14 hexadecimal characters | CDMA2000 networks, replacing the ESN as it ran out of space | Only for genuinely old CDMA-era hardware |
| ESN | 8 hexadecimal characters | Original CDMA and AMPS handsets; the address space was exhausted | Effectively obsolete |
If you have shopped for used phones in the United States you have seen "clean ESN" and "bad ESN" in listings, often on handsets far too new to have an ESN at all. The vocabulary outlived the technology. ESN and MEID come from the CDMA world that Verizon and Sprint ran, where devices were identified by a hexadecimal code instead of the decimal IMEI the GSM world used — and as those networks were retired in favour of LTE and 5G, the identifiers went with them while the slang stayed.
For anything you are likely to be buying today, the answer is simple: use the IMEI. Every LTE and 5G handset has one, the worldwide blacklist and carrier-lock registries are keyed on it, and it is what *#06# shows first. If you are looking at genuinely old CDMA hardware and only an MEID is available, a US-specific lookup can still read that, but you are dealing with a device that will struggle to find a network at all now those systems have been shut down.
Mechanically they differ in shape. An ESN is eight hexadecimal characters and ran out of address space decades ago, which is why the fourteen-character MEID replaced it. An IMEI is fifteen decimal digits with a check digit on the end. A phone from the transitional era can carry both an MEID and an IMEI, printed together in Settings, which is where most of the confusion starts — people assume they are two versions of the same number, and they are not.
And "bad ESN" itself just means blocked. Whether the flag was filed against an ESN, an MEID or an IMEI, the listing is telling you the device is barred from activating — for theft, loss or unpaid financing. Treat the phrase as a synonym for blacklisted, check the IMEI to find out which and why, and price the handset as the Wi-Fi-only device it currently is.
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Common questions
Is an MEID the same as an IMEI?
No. An MEID is a 14-character hexadecimal identifier from the CDMA world; an IMEI is 15 decimal digits used by GSM, UMTS, LTE and 5G networks. A transitional-era phone may display both, but they are separate identifiers and the IMEI is the one current registries use.
What does "bad ESN" mean in a phone listing?
It is American marketplace slang for blacklisted — the handset is barred from activating, usually because it was reported lost or stolen or because money is owed on it. The phrase survives from the CDMA era regardless of which identifier the flag was actually filed against. Check the IMEI to see the specific verdict.
Can I convert an MEID to an IMEI?
Not meaningfully. They are separate identifiers allocated by different systems, and although some old devices derived one from the other, you should not rely on a conversion for a status check. Read the IMEI off the phone with *#06# and use that.
Do modern phones still have an ESN?
No. The ESN address space was exhausted long ago and the networks that used it have been switched off. Any current handset identifies itself with an IMEI, and some older hardware also carries an MEID.
Which number do I need for a blacklist check?
The IMEI. Worldwide blacklist, carrier-lock and warranty lookups all key on it, and it is the number printed on the box and shown by *#06#. If a checker asks for an ESN, it is either very old or aimed specifically at legacy CDMA hardware.
My Settings screen shows both an IMEI and an MEID. Is that a problem?
Not at all — it means the phone supported both network families, which was normal on US hardware for several years. Use the IMEI for any check; the MEID is a historical artefact at this point.