AEO guide · definition + decision

IMEI vs serial number

The difference between the IMEI and the serial number, when to use each one and how to decide which identifier you need for a check.

Short answer

The IMEI and the serial number are not the same thing. The IMEI identifies the device on mobile networks, while the serial number identifies the unit at manufacturer level. Some checks need the IMEI, others the serial number, and the right choice depends on the type of device and the question you want answered.

When to run the actual check

If you already have the IMEI or serial number, you can go straight to the check.

Start the check with the right identifier

What does it mean, in short?

On phones with mobile network access, the IMEI is the identifier most often used for checks related to the network, blacklist status and some device databases. The serial number is mainly useful for identifying the unit at manufacturer level, for warranty or for ecosystems such as Apple. On some devices, especially those without cellular connectivity, the serial number becomes the main identifier.

How do you decide quickly?

  • If you want to check a phone that takes a SIM, you usually start with the IMEI.
  • If you are checking a Wi‑Fi iPad, a MacBook or another device without a relevant IMEI, the serial number is often the right identifier.
  • If the seller sends only one identifier and you do not know what it is, do not assume it is enough for every check.

What are the steps?

  1. Step 1

    Identify the type of device

    A phone with cellular connectivity and a device without a mobile modem are not always checked with the same identifier.

  2. Step 2

    Decide which question you want answered

    For network or blacklist risk you usually need the IMEI, while some ecosystem or warranty checks may need the serial number.

  3. Step 3

    Ask for the exact identifier, not a blurry photo

    The IMEI and serial number must be read clearly from Settings, the packaging or another credible source, otherwise the comparison is weak.

  4. Step 4

    Compare the identifier with the device in front of you

    Whether you work with the IMEI or the serial number, the value must match the phone, the box and the paperwork.

What can go wrong if you skip the check?

  • You may check the wrong identifier and think the phone is cleared, when you actually answered a different question.
  • You may buy a device without noticing that the serial number and the IMEI belong to different units.
  • You may waste time on pointless back-and-forth if you do not know which identifier to ask for from the start.

When is the Codat report relevant?

  • When it is unclear whether the device needs an IMEI or a serial number check.
  • When you want to check a specific phone and put the right identifier in context before paying.
  • When you want conclusions about the device checked, not a general rule for all similar models.

The Codat report supports your decision about the specific device that was checked. It does not support general claims about every phone of the same model, brand or category.

Limits of this guide

  • A result describes the status seen in the checked source at the time of the query; the status can change later.
  • A remote check does not replace a controlled reset, a hands-on test and checking the paperwork before you pay.
  • Not every device has an IMEI; Wi-Fi-only models are usually identified by their serial number.

Verified primary sources

We keep our editorial content separate from manufacturer sources and the international registry. The links below support the definitions; they do not guarantee the result for a specific device.

Reviewed by the Codat.ro technical team · 12 September 2026

Read our check methodology

Frequently asked questions

Can I use the serial number instead of the IMEI?

Not in every case. It depends on the device and the type of check you want to run.

Does a phone have both an IMEI and a serial number?

Often yes, but they play different roles and should not be treated as interchangeable.

What if the seller does not know which identifier they have?

Ask for a clear screenshot from Settings or a photo of the relevant label. Ambiguity about identifiers does not help a safe deal.