GSM or CDMA: Taking your phone to a new carrier should be easy right? Well, not quite as this depend on the technology your phone is using: CDMA or GSM.

GSM phones are the most popular smartphones in the world. But there are also CDMA phones and below is how to tell if your phone uses GSM or CDMA technology.

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How to tell if your phone is GSM or CDMA:
  • If you bought your phone from Sprint or Verizon, then it is probably a CDMA phone.
  • If you bought it from AT&T or T-Mobile, it’s probably GSM.
  • Check your phone’s About settings.
  • Look up your phone’s model number online.
  • We’ll dive deeper into how to determine your phone’s technology in a moment. But first, what the heck is going on with all these capital letters?

Quick Note: Most of the phones used globally is GSM. So, if you are living outside the United States and environs, then you most likely own a GSM supported device. But on rare occasions, CDMA devices makes its way to other regions. So, read this article to know more.

What are GSM and CDMA phones?                 

To be fair, as a phone user, you are not supposed to be worried about these technical terms. But, if you want to save yourself some headaches in the future, you should add knowing the difference between GSM and CDMA to your To Do list.

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The term CDMA stands for Code Division Multiple Access. And the term GSM stands for Global System for Mobile Communication. These acronyms are an easy way to describe two difference forms of network technology that is used in phone networks to send and receive data.

GSM phones make use of SIM cards to link phones in its networks. CDMA phones on the other hand don’t require a SIM card as the phone itself is linked to the network. This is the biggest difference between a GSM and CMDA phones.

In recent years, smartphone companies started making phones that are compatible with GSM, CDMA and LTE technology. The presence of 4G and 5G technology is the game changer. Companies such as Apple, Google, Samsung, Xiaomi, OPPO, OnePlus, and Huawei now make phones that supports all network types.

Will GSM phones work on CDMA networks and vice versa?

The short answer is NO.

Older phones that was created with only GSM technology won’t work on CDMA networks like Verizon or Sprint (Sprint is now part of T-Mobile), even if the device is unlocked. Same goes for phones that were created with CDMA only technology, it won’t work well on GSM networks, like AT&T and T-Mobile.

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A locked phone can be unlocked to work on other networks, but only networks that are compatible with the phone’s technology.

However, as mentioned above, if you have a newer phone, like a Galaxy S20 (or even an iPhone 6s), it will often be compatible with all three technologies as long as it is unlocked.

How to check if your phone is GSM or CDMA

So, you’re asking yourself, “Is my phone GSM or CDMA?” Here are the easiest ways to find out.

1. Which carrier sold you the phone?

Your carrier will usually tell you what technology your phone uses (assuming you bought the phone from your carrier).

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Its general knowledge that, Sprint sells CDMA phones, while AT&T and T-Mobile sell GSM phones. Verizon uses CDMA technology in its networks, but usually sells phones that are equipped with both technologies.

If you bought your device “factory unlocked” or directly from the manufacturer, then it is likely equipped with both technologies.

2. Check your phone’s settings

You can also check if your device is CDMA or GSM from the settings of the phone.

How to check whether your phone is GSM or CDMA using settings:

  • On an iPhone: Go to the Settings app, click on General and then About, and look for an MEID, ESN, or IMEI number near the bottom of the menu.
  • On an Android device: Go to Settings, click on System and then About phone, then click on Status and look for an MEID, ESN, or IMEI number (see picture below).
Device IMEI for Redmi 9 Device

If your phone has an MEID or an ESN number, it’s CDMA. If you see an IMEI number then it’s GSM. If you see both, then your device supports both technologies (lucky you!).

3. Look up the model number of the Cell Phone

You can use those same About settings to find your model number on both iPhone and Android devices. Model numbers are also often printed on the back of your phone.

Once you’ve got your model number you can use a simple Google search to find out network technology your device is using. Below is what it looked like when I looked up my Xiaomi phone model.

My Xiaomi Device Model Number

4. Check for Available SIM card slot

Before the era of 4G and 5G, checking for SIM card slots was the easiest way to know if your device uses GSM or CDMA technology. GSM phones has SIM card slots while CDMA phones didn’t.

But now, it’s more difficult to figure out with the adoption of new 4G LTE and 5G technology. Both GSM and CDMA devices now have SIM card slots. However, the trade mark of CDMA phones still remains absence of SIM card. So, if you get a device without SIM card slot at the side or beneath the battery, then it’s likely a CDMA device.

Which is better between GSM and CDMA?

Whether you own a GSM phone or CDMA phone, both network technology can help you send and receive data. And so long your device can text, make calls, browse the internet etc. the network technology doesn’t really matter.

Although GSM is the more popular than CDMA devices in most regions, that doesn’t mean CDMA devices are whack. So, in clear terms, as far as network technology is concern, both network technology offer same value.

The future of GSM and CDMA

The advancement of technology is fast bridging the gap between GSM and CDMA technologies. And with 2G and 3G phones gradually fading out for 4G and 5G phone, the difference between CDMA and GSM phones might soon become irrelevant.

This upgrade is a good thing but it nothing to help your old phones. For now, you should know get familiar with the type of technology your phone is using.


  1. So we got a refurb from Amazon. It is a LG G7 ThinQ . Model # : LM-G710VM. It is supposedly only for Verizon and when you turn it on… it has stupid Verizon Proprietary Apps on it.
    HOWEVER: ….
    1. It has SIM CARD / SD Card slots.
    2. It has an “IMEI” number on the box and the “About Phone” data.

    We want to switch to ATT because they have a new TOWER in our area and 5G that is 5 bars. Our Verizon TOWER is… at best … 1 -2 bars outside and 3 inside with booster. We also heard that nowdays Verizon phones “automatically” unlock at 60 days from buying it. That’s a mute point because it’s been quite awhile.
    Anyways …. according to you … we can put a GSM SIM in and it will work?? Or is there a “hardware / software” issue that will prevent it ??

    1. JHC it depends. Verizon is also making phones that supports both CDMS and GSM network technology. So, you’ll have to confirm if the phone supports both types of network technology to know if it’ll work on the ATT network you plan on switching to.

      Or, as alternative, you can unlock the device to make use of any network tech and you’re good to go.

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