Just about every smartphone user has had a moment of confusion when they saw the phone bill, and they had no idea why it was so high. Most of the time, this happens because you’ve left your mobile data on, exceeded your monthly data plan, and your carrier charged you for all those gigabytes you used.
But can your phone still be using data even if you’re not actively using it?
Yes, it can.
When you leave your mobile data on, accidentally or not, it still runs in the background. So, even if the phone is in your pocket, it uses mobile data, as if it were connected to Wi-Fi.
Apps use background data.
Apps will tap into mobile data to work as usual so that you can receive emails, social media notifications, Facetime calls, weather information, and so on. Apps can even do automatic updates, and photos will auto-sync. Some of these tasks can be pretty data-intensive and, at the end of the month, the gigabytes can add up.
Some phones and apps disable data backups by default, but that’s not a rule, so, to be safe, it’s a good idea to check how each app uses data. With very few exceptions, apps will continue to work as usual when data is turned on: you’ll get notifications when someone mentions you on social media when you receive a message, you’ll be able to download things from the Internet, use navigation, watch videos, and so on.
Your carrier may charge you for using data, even if you’re connected to Wi-Fi.
One thing that many smartphone users don’t realise is that their carrier may still charge them for using data, even if the Wi-Fi is turned on. It doesn’t always happen, but many people have complained about this, so if you want to avoid extra costs, the best thing to do is disable mobile data when you’re connected to Wi-Fi.
Alternatively, you can limit the way your apps use mobile data by going to Settings -> Cellular and manually deselecting the apps you only want to use on Wi-Fi. The most data-demanding ones are video chat apps, streaming apps, and navigation apps. Instagram also uses a lot of data because it has to download a lot of images and videos.