iPhone battery capacity

Batteries are consumable items. Battery capacity will decline over time, that is completely normal. Apple defines battery capacity as no problem if the battery is 80% or above at 1-year old. There is nothing wrong with your battery.

Abrosome423 wrote:

Also, you can turn off Bluetooth when your not using it and turning off Wi-Fi while in the car or somewhere with no Wi-Fi.

Turning off WiFi and BT doesn't really help in this case.

Wi-Fi and Bluetooth Battery Drain and oth… - Apple Community

If your phones battery capacity has gone down 2% in a week, that means your phone is fine but is taking on heavy use. A good way to slow this down is to turn your brightness down just to where you can see it well enough, close tabs when you are done with them, delete apps you don’t use or need and try to power it off when you don’t need to use it, like when you go to sleep. Turning it off also helps your phone connect to cell towers. Also, you can turn off Bluetooth when your not using it and turning off Wi-Fi while in the car or somewhere with no Wi-Fi.

Because that is what batteries do when you use them. Expect an average of 1% to 2% drop per month.

You're welcome.

It worked for me