Why iphone battery health decrease fastly

Hi Kashifsiraj,

Thank you for posting in Apple Support Communities. We can definitely understand the concern with your battery health. Many things can affect your battery health and lifespan and it is different for each person based on how the device is used.

Based on the information we're seeing here, it looks like you've updated to iOS 14.5 and your battery is recalibrating and this number may not be accurate. You'll want to wait until the calibration is complete to get a more accurate reading. The article above in your related article provides this information and what to do if the recalibration is complete and you are still experiencing the same thing.

You can also check out how to maximize your battery life and lifespan here: Batteries - Maximizing Performance

Hope that helps!