I keep blowing my iPhone’s monthly plan.

iPhone and iPad data plans are expensive enough, so no one wants to be reamed by overage charges. Both AT&T and Verizon have apps that display usage, but they’re awfully finicky and some users have speculated they’re also untrustworthy. Luckily, there’s a quick way to check the data you’ve been using, and it’s built right into your iOS device.

Usage statistics will give you a very close estimate to the data you’ve been using, but don’t solely depend on it if you’re trying to avoid lofty overage charges.

Head to Settings > General and tap Usage. At the bottom of the screen, under Cellular Network Data, your iPhone or iPad will display the Sent and Received data. If you scroll down further, you can reset your usage statistics, which is beneficial if used monthly, on the day your plan starts. But be warned—the iPhone and iPad’s Cellular Network Data don’t always match up with the carrier’s estimates, and you get one guess on which one they’ll bill you for. When you near the cap of your data, it’s best to contact your carrier directly for updated statistics.