This tutorial shows how to view and manage data usage.
INSTRUCTIONS & INFO
From the clock screen, swipe up from the bottom edge of the screen. Note: Data usage tracking on your device and your AT&T account may not align. Check att.com/myatt or the MyATT app for data plan usage.
Scroll to, then tap Settings.
Scroll to, then tap Connections.
Scroll to, then tap Data usage.
Scroll to, then tap Data usage to view measured data usage.