Mobile data is the connection that lets your phone use the internet when you're not on WiFi
To turn on mobile data, you open your phone's settings, find the mobile data or cellular data toggle, and switch it on. The exact steps depend on whether you have an iPhone or Android phone, but the setting is always in the same general area. Once it's on, your phone will connect to your carrier's network and you'll see a data symbol (usually an arrow or "4G" or "5G") appear in your status bar at the top of the screen.
Mobile data uses your monthly data allowance from your carrier plan. If you turn it on and leave it running, apps in the background will use data even when you're not actively using your phone. That's why some people turn it off when they're on WiFi or when they want to conserve their monthly limit.
Key Takeaways
- On iPhone, go to Settings > Cellular > Cellular Data and toggle it on; on Android, go to Settings > Network & Internet > Mobile Network and toggle Mobile Data on.
- When mobile data is on, your phone connects to your carrier's network and shows a data symbol in the status bar.
- Mobile data uses your monthly data allowance, so background apps will consume it even when you're not actively using your phone.
- You can turn mobile data off to save your monthly limit or when you're on a WiFi network, then turn it back on when you need it.
How to enable mobile data on iPhone
Open the Settings app on your home screen. Scroll down and tap Cellular (or Mobile Data on some older iPhone models). You'll see a toggle next to Cellular Data — tap it to turn it on. The toggle will turn green and move to the right.
Once it's on, look at the top of your screen. You should see a signal strength indicator (bars) and a data symbol next to it. On newer iPhones, you'll see "5G", "4G", or "LTE" depending on what network your carrier is using in your area. On older models, you might see just an arrow or the letter "E" (for Edge, an older network type).
If you don't see any data symbol after turning it on, your phone may not have a strong signal in your location, or there may be an issue with your carrier account. Try moving to a different location or restarting your phone.
How to enable mobile data on Android
Open the Settings app. Tap Network & Internet or Connections (the exact name varies by phone maker). Look for Mobile Network or Cellular Network and tap it. You'll see a toggle next to Mobile Data — tap it to turn it on.
After you turn it on, check the top of your screen for a data symbol. You should see signal bars and a data indicator showing what type of network you're connected to (5G, 4G, LTE, or 3G). If nothing appears after a few seconds, restart your phone or move to an area with better signal.
Some Android phones also have a quick settings menu you can swipe down from the top of the screen. You may see a mobile data icon there that you can tap directly without going into Settings, though this varies by phone model.
What to do if mobile data won't turn on
If you toggle mobile data on but it doesn't stay on, or if you don't see a data symbol appear, start by restarting your phone. Power it off completely, wait 10 seconds, and power it back on. This fixes most temporary connection issues.
If that doesn't work, check whether airplane mode is on. Airplane mode disables all wireless connections, including mobile data. On iPhone, swipe down from the top-right corner to open Control Center and look for an airplane icon. On Android, swipe down twice from the top to open Quick Settings and look for the airplane mode toggle. If either is on, tap it to turn it off.
If mobile data still won't work, the issue may be with your carrier account or your phone's SIM card. Contact your carrier to confirm your account is active and your plan includes data. If you recently switched carriers or got a new phone, make sure your SIM card is fully inserted into the slot on the side of your phone.
When to turn mobile data off
You might turn mobile data off to save your monthly data limit, especially if you're on a plan with a smaller allowance. When mobile data is off, your phone can still make calls and send texts, but it won't use the internet unless you're connected to WiFi.
Turning mobile data off also saves battery life, since your phone doesn't have to maintain a connection to your carrier's network. If you're in an area with poor signal, turning it off can actually help your battery last longer because your phone won't keep searching for a stronger connection.
Many people turn mobile data off at night or when they're at home on WiFi, then turn it back on during the day when they need it. There's no harm in switching it on and off as often as you want — it won't damage your phone or your account.
Understanding data symbols in your status bar
When mobile data is on, you'll see a symbol at the top of your screen showing what type of network you're connected to. The symbol tells you how fast your connection is. 5G is the fastest, followed by 4G or LTE, then 3G. Older phones might show an E (Edge) or G (GPRS), which are much slower.
The speed you see depends on what your carrier offers in your area and what your phone supports. A newer phone in an area with 5G coverage will show 5G. An older phone in the same area might show 4G because it can't connect to 5G networks. If you're in a rural area, you might only see 3G or 4G even if your phone is new.
You'll also see signal bars next to the data symbol. More bars mean a stronger signal, which usually means faster speeds. If you have only one bar, your connection will be slower and less reliable than if you have three or four bars.
How background apps use mobile data
When mobile data is on, apps can use it in the background even when you're not looking at your phone. Email apps check for new messages, social media apps refresh your feed, weather apps update forecasts, and map apps download location data. All of this happens automatically and uses your monthly data allowance.
If you have a limited data plan, you can restrict which apps use mobile data in the background. On iPhone, go to Settings > Cellular and scroll down to see which apps have used data. You can toggle off individual apps to prevent them from using mobile data. On Android, go to Settings > Network & Internet > Mobile Network > App Data Usage to see which apps are using the most data, then go to Settings > Apps and restrict background data for specific apps.
Turning off mobile data entirely is the simplest way to prevent background usage. When it's off, apps can't use data at all unless you're on WiFi.
Frequently Asked Questions
Will turning mobile data on cost me extra money?
No. Mobile data is included in your monthly plan from your carrier. Turning it on or off doesn't change your bill. You only pay for the data you use within your monthly limit, and that limit is the same whether you turn mobile data on or off.
Can I use mobile data and WiFi at the same time?
Your phone will use WiFi when it's available and switch to mobile data when WiFi isn't available. You can't use both at the same time for the same task. Most phones prefer WiFi because it's usually faster and doesn't count against your monthly limit.
What's the difference between mobile data and a WiFi connection?
Mobile data comes from your carrier's network and uses your monthly allowance. WiFi comes from a router in your home, office, or a public place and doesn't count toward your limit. WiFi is usually faster, but mobile data works anywhere your carrier has coverage.
Why does my phone use data even when I'm not using it?
Background apps are checking for updates, downloading new messages, and refreshing content automatically. This happens whether you're looking at your phone or not. You can restrict which apps use mobile data in the background through your phone's settings.
Do I need to turn mobile data off when I'm on WiFi?
You don't have to. Your phone will automatically use WiFi when it's available, even if mobile data is on. Turning mobile data off saves a small amount of battery and prevents background apps from using your monthly limit, but it's not necessary.