CDMA vs. GSM, Which One Is the Best for You?

Are you looking to pick a side between CDMA vs GSM, the two major telecommunication standards that are used by the cellular networks worldwide?

It can be a hard choice to choose between CDMA vs. GSM, as both have their own advantages. When in the hunt for a cell phone carrier, you may have to figure out which of these two technologies is the best for you and hopefully this article will shed some light on the whole CDMA vs. GSM issue.

CDMA vs. GSM: Breakdown of the technologies

The Origins of CDMA and GSM

CDMA: Code Division Multiple Access is a technology developed by Qualcomm in the United States, and it is currently the dominant network standard in North America.

GSM: Global System for Mobile communications was invented in 1987 by the GSM Association, an international organization dedicated to developing this standard worldwide.

CDMA was established earlier in North America and thus has a bit more coverage than GSM. GSM on the other hand is an international standard backed by an international organization and the protocol is a more mature and thus more robust. There is no clear winner in the CDMA vs. GSM debate here; it all depends on your needs.

Coverage of CDMA vs. GSM

CDMA: It is mostly used in America and some parts of Asia. It is currently making progress in other parts of the world, but the coverage is still limited compared to the GSM technology. Its support is currently non-existent in Europe because the European Union mandates the sole use of GSM. In North America however, CDMA generally offers a better coverage than GSM in some rural areas because it was deployed earlier. Its network reaches over 270 million users worldwide.

GSM: Being an international standard, it is better suited for international roaming, provided you own a quad-band cell phone (850/900/1800/1900 MHz). The GSM network is also well established in North America, but not as much as the CDMA network yet. Its network reaches over a billion users worldwide.

CDMA is prominent in North America, but GSM reaches a lot more users worldwide (about 1 billion vs 270 million). In the CDMA vs. GSM debate, GSM wins if you plan to travel to foreign countries but CDMA might have a better coverage in your area.

Data transfer

CDMA: The best data transfer technology it has to offer is the EVDO technology, allowing for a maximum download speed of about 2mb/s (about 700kbps in practice), which is similar to what a DSL line has to offer. EVDO is not available everywhere yet and requires a cell phone that is EVDO ready.

GSM: Offers EDGE, allowing for a maximum download speed of 384kbps (around 140kbps in practice). More technologies are being developed on top of EDGE such as HSDPA to boost the transfer rate to over 384kbps in practice. This technology requires an EDGE-ready cell phone.

CDMA offers faster data download and would therefore be the favoured choice for data transfer. GSM is catching up fast however, but its EDGE technology is subject to interferences.

Phone Identification (SIM cards)

CDMA: Your account information is programmed into your cellular phone. If you want to change your phone, you have to contact your carrier and have them reprogram your new phone. You will also need to re-enter your contact list and calendar information into your new phone. If you have a lot of contacts, your carrier might be able to help you perform this task. Some CDMA2000 cell phones support R-UIM cards (Removable User Identity Module) which are used to store account information and contact lists, but these are not very common in North America yet.

GSM: Your account information along with your contact list and other personal data are stored on a SIM card (Subscriber Identity Module). It is a small chip you can freely remove from your phone. When you get a new mobile device, you can simply insert your SIM card into it and it will work with your current account information and contact list. If you travel to another country, it might even be possible to purchase a prepaid SIM card which you can use to avoid roaming fees.

GSM is a clear winner here. The SIM card technology offers many advantages if you plan to travel or switch phone often.  CDMA phones are slowly catching up with R-UIM cards, but cell phones that make use of this technology as still rare.

Which technology is the best for me?

When asking yourself which technology to choose between CDMA vs. GSM, first ask yourself the following questions:

1. Is international roaming important to me? If you travel a lot to foreign countries, you might want to opt for a GSM phone for a better coverage.

2. Am I going to transfer a lot of data using the phone? If you intend to use the phone for mobile web browsing, watching television or downloading MP3s, you might be better off with a CDMA phone. Currently, it offers the best data transfer speed with its EVDO technology and is the clear winner for now.

3. Do I plan to change phone often? If you do, a GSM phone is best for you since you can swap the SIM card to a new device without having to re-enter your personal data.

Once you have established your basic needs, compare CDMA and GSM signals in your region. Also compare the carriers offering both services in your area. Talk to your friends and colleagues and ask them if they are satisfied with their cell phone carrier and how good their signal is. Remember, when choosing between CDMA vs. GSM, preferring a network technology over another also means limiting your choice in carriers.

Aaron January 18, 2007 at 5:19 am

Please note that some CDMA phones use RUIMS (chips) and thus the issue of programming every new phones is not entirely true as is presented above. GSM is not a clear winner in this.

Moonsider Mobile January 18, 2007 at 9:51 am

To my knowledge, RUIM cards have been used in China since 2002 but they are not yet used in North America. I’d like more info on this.

Yes, once CDMA carriers support RUIM cards, GSM will lose one of its big advantage.

hema March 30, 2007 at 4:22 am

A good comparison is given

J.Sch April 23, 2007 at 1:54 am

I’m not sure what “RUIM” cards are, but chips implies something different. i haven’t looked this up because it’s irrelevant. i use CDMA and in no way is GSM a clear winner when it comes to SIM cards as far as my concerns go. the carrier can transfer information from one phone to another. there is also an option to back up the information from the phone to a database, in which case if your phone was stolen, u could still get your contact list. check with your carrier. that would be a great idea for those with GSM phones too.

J.Sch April 23, 2007 at 1:56 am

not to mention, some of the phones that are CDMA have mini SD memory slots supporting up to 2 gigs last i checked. there is the option to save many things on the phone to the SD card, but i don’t think i’ve come across an option to backup my contact list to it. seems like that could be fixed, though.

k_heat April 29, 2007 at 12:54 am

i agree with J.Sch. i’ve gone through about 5 phones so far using CDMA, and i never had trouble transferring anything because when i brought it to verizon they simply tranferred my phone numbers in less than a min. also my past two phones had micro SD so everything else tranferred easily as well. only thing i couldnt transfer was my schedule info. ironically i’m looking into getting a GSM because t-mobile provides better phones for the money. (tmobile and verizon are the best providers around where i am)

J. Eliaser May 11, 2007 at 9:42 am

This is very helpfull information especially to us Africans. I have an idea though, why can’t you guys help us to make some measurements at our side of the world. I’m very much interested in these systems, but I also want to know which system work better in Namibia.
We have deserts, mountains and coastal places. Now, which one is rearly good in both data and voice at these places.
Currently we have both CDMA and GSM in Namibia

s.mani mohan trinath June 9, 2007 at 7:26 pm

really i got good information.thanks to moonsider mobile website.

Manoj June 20, 2007 at 12:22 am

CDMA handset consume 4 times more battery as against GSM handset. So it will be difficult to move during roaming if you not get charging point.

himani June 21, 2007 at 6:27 am

i think cdma is the best technology.Because for communication we need high speed,less noise.

Ifrah July 11, 2007 at 12:52 am

Well both the technologies have their own pros and cons. We can’t as such declare any one the winner. But personally i would prefer GSM.

Cybervlad August 13, 2007 at 10:02 pm

As far as transferring calender, contacts, note, etc.. . get a transfer cable for your cdma phone, usually one can be gotten for under 20 bucks, then download bitpim, an awesome free program. I go through a bunch of phones and this program saves my life because i can just hook my phone to it and move everything that was on my phone to my new phone. I can even make my own ring tones and put them on the phone and if i get a new phone all those tones are saved by bitpim and moved to the new one.

Nate Heller August 20, 2007 at 9:15 pm

I’ve had several CDMA phones, and tried out a GSM phone. I once had problems with a CDMA phone, which I was able to call my service provider and program it over the phone by entering commands, whereas when I had a GSM phone from the same company, I had to wait several days for a new SIM card to arrive.

Depending on the service provider, you don’t always have to take your phone in, and on several occasions, I was able to basically transfer my entire coverage network when I was out of town for a week. I was able to call and explain my situation, and I simply reprogrammed my own phone with their instructions to avoid roaming.

Yasir September 11, 2007 at 6:40 am

Well, We have both CDMA & GSM technologies in our country but GSM is considered as best one and popular than CDMA because CDMA has limited mobility and GSM is country wide.

sundeep September 24, 2007 at 1:53 am

really super

Hobo September 25, 2007 at 8:29 am

Both GSM and CDMA has their respected qualities but there is a flaw within the deception of higher download rates provided by the CDMA. Your mobile/cellular provider would charge you approximately $0.25 per byte downloaded to your phone. So ask yourself this “what’s the point of having higher speed when you’ll go bankrupt over it. Also, majority of new GSM phones have built-in WiFi, this not only go 10x-15x faster (54MBps) than CDMA, it also doesn’t cost to download. With built-in WiFi you won’t have to worry about having Bluetooth, infrared, etc. as you can just use your phone as a network storage over your wireless LAN.

Askhat September 29, 2007 at 8:30 am

Hi all !!!
CDMA in our country is new technology, most people use GSM, but quallity is too low(campare with CDMA). EDGE data transfer depend of quantity of users. Realy speed about 3…12 kbps.

Abhinav Mukherjee October 2, 2007 at 10:05 am

if GSM doesn’t upgrade its data transfer rate, soon it will loose its edge over CDMA. Another point is that CDMA offers better coverage even in some of the most secluded corners of a building.

Phil Starn October 8, 2007 at 1:57 pm

Thank you everyone for your comments. There is a lot of very valuable information in there! :)

Ramdayal Prajapati November 6, 2007 at 12:47 am

I think that CDMA in not a good technology because we cannot change the service provider and are limited to it.

Dennis AA November 7, 2007 at 9:05 am

well great comparison but for the data comparison because gsm does offer faster data speed than cdma. look up the speeds for class 7.8 UMTS/HSDPA. it is higher that 700kbps and there are even higher classes available oversease.
so more research

julio November 7, 2007 at 3:00 pm

In worldwide, GSM has cheaper phones probably because 2% Qualcomm CDMA royalties per unit, plus the high GSM production scale. Nokia and others phone producers gave up CDMA, so there is more tension to CDMA carriers. I think some aspects of business and competition should not mix up technical differences (in tech terms, CDMA is better), but market is everything in real-world. For smartphones, GSM has better and more advanced phones; 3G improved data speed for GSM, almost comparing to CDMA. So, the best cell phone is that cover my needs in two years, at most. Like CD and DVD, I think new technologies will arise and make this discussion irrelevant.

Andy November 13, 2007 at 9:46 am

Julio brings up a good point: Phone costs for GSM phones are much less. Particularly if you are buying the latest and greatest version of the phone you want. This is because of production volumes:
GSM = ~ 1 billion users worldwide.
CDMA = ~ 250 million users worldwide.

Finally: I travel a lot for work – everywhere in the world. I have had some colleauges with CDMA phones who are told their phone will work in country X. Theirs *never* does, but my GSM phone works every place I have ever been. I second the article’s author in saying that if you travel internationally for work or pleasure, the absolute best bet is to buy a GSM phone and get it unlocked. I drop in local SIM cards in the countries I visit and have a local number and local rates, etc.

John December 3, 2007 at 9:54 am

My gsm phone is garbage it does not work it is the worst network of phones i have ever had. Im in buisness class and we are discussing GSM phones. I have just bought a GSM phone 2 months ago and it already broke it is the worst network. I am advising all of u never to buy a LG PHONE

bhuwan December 7, 2007 at 5:36 am

i think gsm is the best bcoz it keeps the personal records while changing the set.

Thibault January 9, 2008 at 5:16 pm

Well…actually, GSM has considerable coverage in many areas in North American right now. Just go to T-Mobile’s website and click on their “coverage” link and you’ll see how widespread the map for GSM is.

One important thing to consider is not just generally whether CDMA or GSM has wider coverage in N. America. It’s important to consider: do you live in the rural areas or do you travel to rural areas a lot? Many urban folks don’t go to rural areas much and so it doesn’t really mean much if there is wider CDMA rural coverage for them because they won’t get to use that “selling point.”

Walter January 14, 2008 at 3:42 am

I know you think you understand what you thought I said , but I’m not quite sure what you heard is what I meant…… I think?

Luci January 14, 2008 at 4:41 am

Most people doesn’t even know what gsm and cdma means. The winner depends on the careers; the careers with better coverage at low costs are going to take the lead.

Luci January 14, 2008 at 4:43 am

i mean gsm is the leader at this time, we’ll see in the future what’s gonna happen

Elie February 29, 2008 at 11:42 am

Julio hit the nail on head when he stated there are a wider range of phones and manufacturers supporting GSM.

If I was a cell phone manufacturer, which network do you think I’m going to target first? CDMA with mayby 250 milion users? or GSM with 1 billion users?
I will quickly support GSM first, look at Apple, it came out only supporting GSM, where is the CDMA model? does it even exist in Apples road map? I think not!!

Alot of new cell phones are only supporting GSM mailny due to wider coverage (more sales)… Nokia’s N90 series some of the coolest phones only support GSM.
That leave the leftover garbage supporting CDMA. Believe me, I am on a CDMA network and am extremely frustrated at the fact that my wireless company supporting CDMA has the crappiest selection of phones.
They do offer the HTC touch, but I would prefer an Iphone over that big time.

There is very little incentive for cell phone developers to create CDMA based phones and that’s causing major issues for the format.

I do believe CDMA offers slightly better quality as well as tranfer rates, however what’s the point if it’s crippled from a product selection perspective.

purket March 21, 2008 at 4:58 am


i agree with you on how CDMA phones are worse than GSM phones. however, i hate to break it to you but apple did go to verizon wireless before they went to at&t. it’s just that verizon turned them down. stupid move for verizon? perhaps. (i personally think it was stupid for them to turn apple down) and one of the most awesome features of the iphone is the internet and how easily it is for us to view and use. i’ve compared EVDO to EDGE on the iphone and it took about 20 seconds to load google. I immediately understood why apple went to verizon first for their EVDO.

One correction of the guide: until verizon came out with backup assistant, sim was definitely one of the top reasons to choose gsm. But with backup assistant, sometimes it’ll be faster syncing the contacts to ur new phone through verizon than it would take for you to swap the sim card. And if you get your phone stolen/lost, your contacts are gone forever whereas the cdma carrier can just send it right back to your new phone. But CDMA still can’t transfer calendar. And if you are a traveler, you won’t be able to take advantage of international countries’ prepaid sim cards.

this guide was pretty good and had the right questions to ask yourself when choosing a carrier (except the third question). I personally think asking your friends and colleagues should be the third question.

Phil Starn March 21, 2008 at 3:53 pm

Thank you for your very constructive comments everyone.

Greg Patrick April 2, 2008 at 8:34 am

Now, I am really confused. One site say CDMA is better, another site say GSM is better.

As far as the using the battery on CDMA. It depends on what type of phone you have. If you have a tri-mode phone. It will use a digital signal first. So, it will use less battery power.

Donovan Hill April 7, 2008 at 4:15 pm

One important thing with GSM is the SIM card, but it isn’t just the contact list. It’s the lock in. If you have an unlocked phone you can take your phone to the carrier with the best deal and not get locked into a contract.

obinna ekwom May 20, 2008 at 5:39 pm

this is a well thought out publication, it is excellent, punchy and direct resourceful knowledgr for anyone that stumble s upon it. well done

jimmy t May 27, 2008 at 3:56 am

The contacts-on-the-SIM-card issue is moot: first, phones that store contacts on the SIM can only store name and a single phone number, so most phones store their contact lists in internal memory anyway, and second, GSM carriers (T-mobile for sure) also provide the service of backing up your contact list on the system. The two significant issues (where your area is well-covered by both types of networks) are battery consumption, which is about doubl for CDMA as it is for GSM, and the ability to unlock phones and transfer to a new carrier.

stanza June 10, 2008 at 12:38 am

using a RUIM card on a CDMA enable phone now gives me the choice of changiing my phone without consulting my operator. its crasy but am cool wit CDMA than GSM which i used before changing to CDMA. i luv the speed of data transfer and dont intend changing back for now

Luis June 20, 2008 at 12:22 am

Here on Puerto Rico Verizon Wireless had the most advanced mobile infrastructure in coverage and in its EVDO. About a year ago, the Mexican company America Movil bought Verizon in PR and started to add a GSM network working parallel to the CDMA network left by Verizon Wireless. I had Verizon and is WAYY better in coverage inside buildings, while the GSM network coverage is bad. At last, the other two GSM carriers have the same coverage problems due to the physical characteristics on the island, all of the CDMA carriers have a much better quality of voice and data speeds and an incredible better signal strength at all places. CDMA is much better than GSM, depending on the physical characteristics of your place.

Abena November 24, 2008 at 3:07 pm

i work with a telecommunication company that provides CDMA technology in Ghana. I was using a GSM phone and i can say the network is really bad. Really Bad service. Since i started using CDMA, i haven’t had such problems.
I think there’s no clear winner here. They all have their advantages and disadvantages but i will choose CDMA over GSM any day.

Zaheer Hasan August 17, 2009 at 12:28 am

Both the technology having their own benefit so we could not compare with each other as they work totally on diffferent technologies.

Danu December 24, 2009 at 10:37 pm

Hmmm… for the operator side, CDMA is the clear winner, but from the customer point of view (various handset) GSM wins hands down. In my country both has good coverage (almost equal, GSM won by a hair in rural areas), and I’m forced to buy both handset. CDMA operator rate is far lower than the GSM operator but the handset availability suck, and on the service side they’re not as sophisticated as Verizon in the US (no contacts backup, no MMS, no BREW although the handset support it, no Long SMS, no Int’l roaming) in the end I use CDMA for voice call, and GSM for everything else (including contacts backup). When travelling abroad, I don’t bother to bring my CDMA handset.

Osteologaiton January 11, 2010 at 5:21 pm

Another thing to consider is that sim cards slow the phones down. I’ve seen, multiple times, the same phone but different technologies perform differently. The CDMA phones boot faster and crash less. Case in point, I have a Palm Treo Pro for work. I am one of 6 people out of 2000 in my company with AT&T the rest being Sprint. Every time I use it I have issues. I call tech support and they tell me only the gsm phones have these issues. I personally have Sprint, Ironic I think, and love the large 3g network and speeds in the US.

goutham February 3, 2010 at 12:14 am

nice for basic info.

shobhit February 5, 2010 at 7:10 am

i want high and fast internet speed. which technology i should prefer?

Dc2 February 5, 2010 at 8:35 am

Osteologaiton Palm Treos are garbage they are prone to crashing!

PRADEEP March 15, 2010 at 3:27 am


Realy great information …
I think GSM is better now days.

JB April 5, 2010 at 4:02 pm

Stupid comparo. CDMA beats GSM hands down in every way except global coverage. SIM cards are a thing of the past especially now days with tools out there that can easily store contacts and settings which makes it a breeze to switch phones. I personally just had to replace my Verizon HTC smartphone and the second I turned on the phone and logged into my account it downloaded all my contacts, all my pictures, music, etc. Then it updated all the settings on my new phone to mirror that of my old phone (including ringtones, picture contacts, playlists… everything. helpful when replacing a lost phone). So it was instantly like my phone was never lost. SIM is old technology. Get with the times.

JB April 5, 2010 at 4:07 pm

Oh and btw Purket it transfers calendar also.

hith April 5, 2010 at 8:21 pm

I think CDMA users are hell bent to prove that it is the best.
You loose your free will if you chose CDMA. It is as simple as that to understand.
GSM rocks.
And internet speed, every body knows that the wireless technology today is still in adolescence.
It is clearly obvious in this article that every merit of GSM is being countermanded by just one merit that CDMA holds which is more coverage in Americas.Who care America when 80% of mobile phone users live out side America.

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