After Apple received a spate of bad publicity about how it chose to throttle older iPhones with degraded batteries, it apologized and offered a battery replacement program for many phones at reduced cost. But it also pledged to improve how it disclosed to users the state of their battery.
It’s a little hidden, as you have to launch Settings and then tap Battery to see monitoring details. Tap Battery Health, and you see two important stats.
Maximum Capacity measures the peak charge that the battery can hold. (Mine is currently 91 percent after about 14 months of solid use.) It’s normal for this to decline slowly over a period of time, and decline faster the more frequently you run through a charge on your phone.