Every iPhone app uses a varying amount of data, depending on many factors. Whether an app uses up gigabytes or just megabytes per day, the data usage can quickly add up. Luckily, your iPhone makes it easy to keep track of how much data each app uses. so you can ensure you don't go over your data allowance each month.
How to Track Data Usage for Third-Party iPhone Apps
To find out how much data installed apps are using on your iPhone, go to Settings > Cellular Data. Here you'll find a list of all the apps that have used cellular data. Underneath each app name, you should find the exact figure used by the app in alphabetical order since your iPhone started tracking it.
It would be nice to be able to rearrange the list by data usage. But at least you can scroll through the list and see where most of your data is going. This can also give you a better idea of which apps you are using a lot.
If you find a specific app is using more data than you would like, you can switch off data usage for that app, allowing it to depend entirely on Wi-Fi networks. This is especially useful if you're on a limited data plan, as it will help to limit your cellular data usage.
What is also a helpful feature is the ability to Reset Statistics at the bottom of the list. This will help you to keep track of your mobile data usage over a longer or shorter period, to really pinpoint which apps the data usage is being blown on.
How to Track Data Usage for Native iOS Apps and Systems
To find out how much cellular data native iPhone apps and settings have used, go to Settings > Cellular > System Services. You will find this at the very bottom of the screen. You can then see how much data iMessage, Apple Maps, Siri, iTunes, Exchange accounts, Voicemail, your Home Screen, and more iPhone features are using.
Keep Track of Your iPhone's Data Usage
As well as tracking mobile data usage via the iOS Settings, you can also track your data usage via your carrier's website. Many carriers will offer information on the mobile data used by different apps, giving you multiple ways to track the usage.
By following these simple steps, you should now be able to track the data usage of all of your individual apps. By getting an idea of how much each app uses, you can decide which apps to allow access to mobile data and which apps to keep strictly on Wi-Fi.