Signalchecker.com

Check Cell Coverage by zip code for all US networks with one search


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    Cell Signal Coverage data for the whole of the USA

    Our database contains cell coverage information for AT&T, USCellular, T-Mobile, and Verizon.

    Results show indoor and outdoor coverage for voice calls, 3G data, 4G (LTE) data, and 5G data for every zip code in the USA for each carrier.

    What is cell phone coverage and signal checking?

    Before you sign up with a new carrier, you need to be sure that you can get good reception - both good coverage and a reliable signal - where you live and work. If you can't, you might not be able to make calls, send messages, or use apps when you need to.

    Over 90% of the US has good cell coverage; it's generally only rural areas where you might not get a signal. However, not all carriers provide the same level of coverage across the whole country. They can vary massively from one state to the next. So, a carrier that works for someone in a Southern State might not be the right choice for someone in the Northwest.

    Our Signal Checker shows the coverage and signal strength for your zip code and helps you see which carrier will give you the best service. We check all the main carriers at once, saving you the time and effort of having to visit them all individually.

    Who provides cellular coverage in the US?

    There are three main carriers that provide cellular coverage across the US. In order of size, they are:

    • Verizon
    • AT&T
    • T-Mobile

    A fourth company, Sprint, merged with T-Mobile in April 2020. While existing customers won't have to switch for the foreseeable future, the Sprint brand has been retired and new customers must join T-Mobile. The move brings T-Mobile level with AT&T in terms of size.

    These companies build and maintain their own cellphone network infrastructure, including the phone towers that you can see all around your towns and cities. The more of these towers you have in your area, the better the signal will be from the carrier that owns them.

    What other carriers are there?

    As well as the main carriers, there are two other categories of carrier that you can choose from.

    • Regional carriers: some carriers are only available in certain regions. USCellular is the fourth-largest carrier in the US - their own network covers around 10% of the country, and they partner with the other three carriers to flesh out their coverage elsewhere.
    • MVNOs: Mobile Virtual Network Operators don't maintain their own networks, they rent and resell coverage from one of the three main carriers. There's over a hundred of them, and some are also regional. Big names include Virgin Mobile, Google Fi, Mint Mobile, and Cricket Wireless.

    MVNOs will often offer prepaid deals. This means you don't have to sign a contract, but pay in advance for an allowance of data and calls instead. These often work out a little more expensive, but the convenience might be worth it, especially if you don't use your phone that much.

    What types of cell coverage are there?

    Carriers provide several different cellular services. Coverage for each can differ from one region to the next, and the one that you use can also be dictated by what you're doing on your phone and what type of phone you've got.

    • 5G: the latest type of data connection - it's truly rapid, with speeds over 1Gbps. It's also still very new, so coverage is patchy at best. It has been rolled out in parts of large cities around the country, but you'll have to wait several years before it becomes common nationwide. The new iPhone 12 supports 5G.
    • 4G (LTE): the previous generation is used for data, as well as voice calls (depending on your phone and carrier). It has over 90% coverage around the US, and all modern smartphones support it. You can get speeds over 150Mbps.
    • 3G: now used for data and voice where an LTE connection is not available. You won't use it much, but if you do you could get speeds of 7.2Mbps.
    • Voice: the most basic type of coverage is voice (or 2G), used for calls and text messaging over SMS (iMessage and similar apps use the 4G or 5G network).

    Will my phone work with every carrier?

    As a general rule, your phone will work with every carrier even if you buy it outright, separate from your contract. 

    There can be some technical issues, though. Different carriers' networks run on different frequencies, and your phone needs to support these. Most modern phones do support them all. 

    For voice calls, the situation also used to be complicated. Carriers used one of two types of cellular tech - GSM or CDMA - and you needed a phone that was compatible with whichever service your carrier used. However, this only applies to 2G and 3G connections. 

    LTE (for 4G) is a different technology again, so unless you're still using a very old device you don't need to worry about it.

    What affects my cell phone signal?

    The main thing that affects your cell signal is your carrier's coverage. If you're literally stood next to one of their cell towers you'll have a perfect signal. But if you're a long way from a tower, that signal may come and go. This can affect your data download speeds, or result in dropped calls.

    There are other factors, too:

    • Your environment: the signal from a cell tower can be blocked by large physical objects. Your signal can be worse indoors than outdoors, in the basement, or if you're surrounded by skyscrapers or mountains.
    • The weather: bad weather, including very heavy rain, snow, or thunderstorms, can temporarily knock out your phone signal.
    • Crowds: if you're in a crowded place, with lots of people trying to connect to the same cell tower at the same time, you're likely to find the speeds a lot slower - and you might not be able to connect at all.
    • Your phone: every phone gets its signal through a built-in antenna. Some of these are better than others.
    • Travelling: if you're on a train, or in a moving car, you might find your cellphone signal is inconsistent. This is because you're constantly moving out of the range of one cell tower, and into range of another, and your phone has to keep switching connections between them.

    How can I improve my phone signal?

    Sometimes you can't get a phone signal right when you need it most. Don't worry, there are some things you can try.

    • Move upstairs: many of the kinds of things that can block a phone signal are nearer the ground, so just going upstairs, or finding higher ground outdoors can help. 
    • Go to a window: signal strength is often better outdoors than indoors, so stand near a window - and open the window if you can.
    • Go outside: if standing near a window doesn't help, going outside should do.
    • Turn your phone off and on: when a phone disconnects from the network it can sometimes struggle to reconnect again. Switch your phone into airplane mode quickly, or turn it off and turn it on again, to force the device to connect to the network once more.
    • Try Wi-Fi calling: if you're having problems with voice calls, consider switching to a Wi-Fi calling app. There are loads available for both iPhone and Android - Skype lets you call standard phone numbers, while you can use WhatsApp to call your regular contacts.
    • Use a signal booster: are you able to get a signal outside your home, but not inside? You could consider getting a signal booster, which uses an external antenna and amplifies the signal throughout your home. Some carriers even sell their own signal boosters.
    • Switch to a better carrier: if you're having constant problems with poor reception, use our signal checker to see if there's a carrier with better coverage in your area.

    How do I check my cellphone coverage?

    So what's the best way to discover which carrier has the best cellphone coverage where you live? Simply scroll back up to the top of the page, enter your zip code into the box, and we'll do the rest. 

    We'll show you whether you can get voice, 3G, 4G, and 5G coverage from America's four biggest carriers.

    What these results mean

    These results show what the cell signal for each network should be in the postcode you've searched for.

    We are confident that these results will be accurate, however sometimes signal conditions may vary slightly within a zip code.

    Cell phone signal levels can be affected by a number of different things:

    Your location - the further away you are from a cell phone tower the weaker your signal will be, as the signal gets weaker this affects the signal quality which will reduce your data download speeds.

    Your local environment - hills, buildings, being in a basement or underground will all affect your cell signal.

    Travelling - if you are in a car or train and moving fast you may find your signal will be affected as you move from strong signal areas to weak or no signal areas.

    Your phone - some models of phones are just better at getting a signal than others, a phone with low battery can also affect the way your phone works depending on the model.

    The Weather - believe it or not even the weather can interfere with your cell signal, heavy rain and snow can degrade the signal temporarily.

    Before choosing a cell phone network always check their own coverage checkers:

    AT&T Coverage Checker

    T-Mobile Coverage Checker

    U.S. Cellular Coverage Checker

    Verizon Coverage Checker