Whenever you use the internet, and you're not on Wi-Fi, you'll be using mobile data. Here's how to keep an eye on how much you're using and reduce it if you need to.
Tap Mobile data usage or Cellular usage (depending on your network).
The page shows your usage through a certain 'period'. The default setting is since you last factory reset your phone, so if you're looking at this page for the first time, it's probably showing you all the data that you've used since you got the phone. Tap Reset statistics at the bottom of the page to start a new period.
The data usage page also shows you how much data is being used by apps. If you can see a particular app using a lot of data, you can turn off data usage for that app by tapping the switch next to it. This'll stop the app from using your mobile data, but it'll still be able to use Wi-Fi.
Apple also introduced a feature called 'Wi-Fi assist' from iOS 9 onwards. This feature will swap between Wi-Fi, and mobile data, depending on which connection is strongest, to try and keep your browsing as smooth as possible. If you don't get a lot of data with your mobile plan, you might want to turn this off by going to Settings > Mobile data > Wi-Fi assist.
Go to Settings > Data usage, and you'll see a graph showing your data usage over a certain period. The coloured bars can be adjusted to set a warning, and also a limit, to stop you using too much data. Further down the page, you'll also see a list of your apps, and how much data they use.
You can also download alternative data monitoring apps from the Play Store.
The 'Data Sense' app is included in all versions of Windows 8. To open it, swipe your Home screen from right to left, and tap Data sense (the list is usually in alphabetical order). The app lets you see how much data you're using, and how much data individual apps use. You can also set a data limit, so you'll never use more than your allowance.
To set a limit, press the Settings icon at the bottom of the screen, and set both the Data limit and also the date you want it to reset each month. That lets you track your data usage between bills.
To get to your data usage screen, open Settings > Network & Wireless > Data usage and you'll be able to see how much mobile data your device has used, and how much Wi-Fi it's used. Tap Usage details under your network name to see how much data has been used by individual apps. On the same line, over to the right-hand side tap Edit to customise your data limit and usage period.
If you're running anything earlier than BBOS 10.3, then you'll need to download a data usage app, available in the BlackBerry World app store.
BBOS 10.3 comes with an in-built usage monitor. Go to Settings > App manager > Device Monitor. You'll need to press the Mobile data option at the bottom of the screen to check the mobile data usage. Tap the three dots in the lower right corner to customise your data limit and usage period.
It's important to remember that in-built usage monitors might measure the data slightly differently to your network, so if you're setting limits, it's often a good idea to set them a little lower than your actual allowance. If you want to know exactly how your network measures your data, you'll need to contact them directly.
Hopefully that's you sorted, but if you need more help, you can get in touch with a Team Knowhow Expert here.