IMEI vs Serial Number vs MEID vs EID: What’s the Difference?

Open Settings › General › About on a recent iPhone and you’ll see a wall of numbers: Serial Number, IMEI, IMEI2, MEID, EID, maybe ICCID. Android phones show a similar list. They look alike, but each one identifies something different — and using the wrong one is the most common reason an unlock request or an IMEI check fails.

Here’s the short version: the IMEI identifies the phone to mobile networks, the serial number identifies it to the manufacturer, the MEID is the old CDMA equivalent of the IMEI, and the EID identifies the eSIM chip. Below is the full breakdown.

Comparison table

Only one of these, the ICCID, changes when you swap SIM cards. The IMEI, MEID, EID and serial number are tied to the hardware for its whole life.

IMEI: the network identity

The International Mobile Equipment Identity is a 15-digit number defined by 3GPP for GSM, UMTS, LTE and 5G. It has three parts: an 8-digit TAC (brand and model), a 6-digit serial and a final Luhn check digit. Our guide what is an IMEI number covers it in depth.

Carriers record SIM-lock, financing and lost/stolen status against the IMEI, and the GSMA blacklist is keyed by it. So when you want to know whether a phone is usable on a network, the IMEI is the number you need — for example for a GSMA blacklist check.

Dual-SIM phones have two IMEIs, one for each line. Both point to the same device. See why phones have two IMEI numbers.

Serial number: the manufacturer’s identity

A serial number is the manufacturer’s own label for a unit. There’s no global standard: Apple uses 10–12 alphanumeric characters, Samsung typically uses an 11-character code, and other brands use their own formats. Wi-Fi-only iPads, Macs, AirPods and Apple Watches without cellular have only a serial number — no IMEI at all.

The serial number is what the manufacturer uses for warranty, AppleCare, repair history and activation records. Older Apple serials even encode the factory and production week; learn to read them in how to decode an Apple serial number.

MEID: the CDMA legacy

The Mobile Equipment Identifier is the CDMA-network counterpart of the IMEI. It is 14 characters long and written in hexadecimal, so it can contain the letters A–F. It replaced the even older 8-character ESN (Electronic Serial Number) when CDMA carriers ran out of ESNs.

CDMA was used mainly by Verizon and Sprint in the US and by a handful of operators elsewhere. Those networks have now been shut down in favor of 4G LTE and 5G, so the MEID matters much less than it used to. You’ll still see it on many phones, and some older US carrier systems and records may ask for it.

On multimode phones that support both GSM and CDMA — including iPhones — the MEID is usually just the first 14 digits of the IMEI. Drop the last (check) digit from the IMEI and you have the MEID. If you need to map an iPhone’s MEID to its second IMEI or serial, use the MEID → IMEI2 → serial conversion.

EID: the eSIM chip number

The EID (eUICC Identifier) is a 32-digit number that identifies the eSIM chip soldered inside the phone. Carriers use it to push an eSIM profile to that specific chip, so you may be asked for it when activating an eSIM through a store or by QR code.

A few points that confuse people:

• The EID belongs to the chip, not to a line. You can store several eSIM profiles on one chip, and they all share the same EID.
• Each eSIM profile has its own ICCID, just like a physical SIM card.
• Phones without eSIM don’t have an EID.
• The EID is not used for blacklist or carrier-lock checks — those use the IMEI.

Find it under Settings › General › About on iPhone, Settings › About phone › SIM status or Status information on Android, or by dialing *#06# on many newer phones.

Which number should you use?

Mistakes that make checks and unlocks fail

• Sending the ICCID instead of the IMEI. Both are long strings of digits, but the ICCID starts with 89 and is 19–20 digits long. An IMEI is always exactly 15 digits.
• Sending the IMEISV. Some Android menus show a 16-digit IMEISV. Drop it — checks need the 15-digit IMEI from *#06#.
• Typing the MEID with letters into an IMEI field. A hexadecimal MEID such as one beginning with A0 won’t validate as an IMEI. Use the phone’s IMEI instead.
• Confusing the EID with an IMEI. If the number is 32 digits, it’s the EID and no IMEI check will accept it.
• Mixing up 0/O and 1/I in serials. Apple serials never contain the letters O or I.

Before you submit any IMEI, it’s worth running it through a validator — our check digit guide explains how it works, and you can test any number here:

How to cross-check the numbers on a used phone

1. Dial *#06# and note the IMEI(s), plus the EID if shown.
2. Open Settings and compare the IMEI and serial with the box and SIM tray.
3. Run a model, color, storage and Find My check or an All-in-one check by IMEI/serial and confirm both numbers belong to the same model.
4. For non-Apple phones, a manufacturer + model check confirms the brand and model behind the IMEI.

If everything matches and the records are clean, you can be confident the phone is what the seller says it is.