Android
Set Start Date for Data Usage Stats auf Android
Android resets the mobile data usage graph on the first day of every calendar month by default. If your carrier bills you from a different date, the numbers in Settings never line up with your actual invoice.
This reset day only controls how the system counts and displays usage locally. It does not change your data plan, your limit, or your carrier's real billing cycle.
To match the two, go to Tap on Settings ➔ Tap on Network & internet ➔ Tap on SIMs ➔ Choose a SIM card (Dual SIM) ➔ Tap on Data warning & limit ➔ Tap on Mobile data usage cycle ➔ Set a Date and tap on Set.
On dual-SIM phones, repeat these steps for each SIM separately. Usage cycles and warning limits are tracked per SIM, not for the device as a whole.
This setting mainly affects tracking and warnings on the device itself. If you depend on carrier-side data caps or throttling, confirm the exact cycle with your provider, since the network-side counter can differ slightly from what Android shows.