Where to find your data usage on iPhone

Your iPhone tracks how much cellular data each app uses, and you can see the total in Settings. Open Settings, tap Cellular, and scroll down to see which apps have used data in the current billing period. The number next to each app shows megabytes (MB) or gigabytes (GB) consumed since your last reset.

At the top of the Cellular screen, you'll see your total cellular data usage under "Cellular Data". This is the number your phone bill is based on. If you're on WiFi most of the time, this total should stay much lower than your plan allows.

The data shown here resets on the date your phone bill renews each month. If your billing cycle doesn't match the calendar month, the numbers won't line up with what your carrier shows — that's normal and not a sign of a problem.

Key Takeaways

  • Open Settings, tap Cellular, and scroll to see total data usage and which apps consumed the most.
  • The total shown resets each month on your billing cycle date, which may not be the first of the month.
  • Apps using data in the background, like email and location services, often consume more than you expect.
  • Turning off Cellular Data for specific apps prevents them from using your plan's data when WiFi is unavailable.
  • WiFi information automatically switches to cellular when your WiFi signal weakens, so disabling it prevents surprise overages.

Which apps are using the most data

The Cellular screen lists every app that has touched your data connection, ranked by usage. The apps at the top have consumed the most. Video streaming apps like YouTube and Netflix typically lead, followed by social media apps like Instagram and TikTok, which auto-play videos.

Some apps surprise you because they work in the background. Mail, Maps, and weather apps refresh automatically even when you're not looking at them. If you see an app you barely use near the top of the list, it's probably refreshing in the background.

Tap any app name to see a breakdown of how much data it used. This helps you decide whether to turn off background data for that app or uninstall it entirely.

Turning off data for apps you don't need

If an app is using too much data, you can prevent it from accessing cellular data without deleting the app. Go to Settings > Cellular, scroll to the app, and toggle off the switch next to its name. The app will still work on WiFi, but it won't touch your plan's data.

This is especially useful for apps that refresh in the background, like email or weather. Turning off cellular data for these apps means they'll only update when you're on WiFi, which saves data without losing the app's functionality.

You can turn the toggle back on anytime if you need the app to work away from WiFi. There's no penalty for switching it off and on.

Disabling WiFi information to prevent hidden overages

Your iPhone has a feature called WiFi information that automatically switches to cellular data when your WiFi signal gets weak. This is convenient but dangerous if you're near your data limit — you might not notice the switch and suddenly use cellular data you didn't plan on.

To turn it off, go to Settings > Cellular and scroll to the bottom. Toggle off WiFi information. Now your phone will stay on weak WiFi instead of jumping to cellular, which means you'll notice the slow connection and can move closer to your router.

Disabling WiFi information is especially important if you're on a limited plan or if you've had surprise overage charges before. The tradeoff is that you'll experience slower speeds when WiFi is weak, but you'll stay in control of when cellular data is used.

Checking data usage on WiFi separately

Your iPhone also tracks WiFi data usage, though your phone bill doesn't include it. To see how much data you've used on WiFi, go to Settings > WiFi, tap the information icon (i) next to your network name, and look for "Data Over WiFi".

This number is useful if you're on a home WiFi plan with a data cap, or if you're using a mobile hotspot from another device that has limited data. Knowing which apps consume the most WiFi data helps you manage your home network's bandwidth.

Unlike cellular data, WiFi usage doesn't reset on a billing cycle — you have to reset it manually by going back to that same screen and tapping "Reset Statistics" at the bottom.

Understanding the difference between MB and GB

Data is measured in megabytes (MB) and gigabytes (GB). One gigabyte equals 1,000 megabytes. Most phone plans are measured in gigabytes — a typical plan might be 5 GB or 10 GB per month.

When you see an app has used 500 MB, that's half a gigabyte. A one-hour video stream on YouTube uses roughly 500 MB to 1 GB depending on quality. Scrolling social media uses much less — usually 5 to 20 MB per hour.

If your plan is 5 GB and you've used 3 GB halfway through the month, you're on track to go over. Most carriers let you see your usage on their website or app, which is often more up-to-date than your iPhone's count.

Resetting your data counter each month

Your iPhone resets the cellular data counter automatically on your billing cycle date. If you want to reset it manually — for example, if you're testing how much data a specific app uses — go to Settings > Cellular, scroll to the bottom, and tap Reset Statistics.

After you tap Reset Statistics, the counter goes back to zero and starts counting again. This erases the old data, so only do it if you're sure you won't need those numbers later.

Some people reset their counter at the start of each billing cycle to match their carrier's count. If the numbers don't match after a month, the difference is usually because your carrier counts data slightly differently or because you used data before the billing cycle officially started.

Frequently Asked Questions

Why does my iPhone show more data usage than my carrier does?

Your iPhone counts data from the moment you turn it on, while your carrier's count may start a few hours later on your billing date. The difference is usually small. If it's large, check whether you've been using a VPN, which can inflate the count because it encrypts all your traffic.

Can I see data usage for a past month?

No, your iPhone only shows the current billing period. To see past months, check your carrier's website or app — they keep a history of your usage. Your carrier's numbers are the official ones your bill is based on.

Does turning off cellular data for an app stop it from working completely?

No, the app still works on WiFi. It just won't use your cellular plan's data. If you're away from WiFi and try to use the app, it will show an error or load very slowly, but the app itself isn't deleted or broken.

What uses the most data on an iPhone?

Video streaming uses the most by far — one hour of video can use 500 MB to 3 GB depending on quality. Social media apps with auto-playing videos come second. Email, maps, and weather apps use much less unless they're refreshing constantly in the background.

Should I turn off background app refresh to save data?

Turning off background app refresh saves some data, but the bigger savings come from turning off cellular data for specific apps. Background refresh uses data, but most apps don't refresh constantly. Start by disabling cellular data for apps you don't need away from WiFi.