Why battery percentage stopped reaching to 100 percent in iphone?

Though i don't feel any drainage problem,
but lets say when it reaches to 99 percent it won't increases to 100 percent
but if i off/on phone it shows 100 percent and "plug" sign means its fully charged remove charger

Depends, on the iphone, if it's the 4 than it's because it's old, if it's the 5 or any latest versions than you should go get that checked out.

  • Why won't my iphone 8 plus charge to 100 percent and stays at 98 percent? I don't leave it all night charging. I always wake up around 7 then charge it for like 2 or 3 hours and it will stay at 98 percent, but when I restart it, it would go to 100. And I just recently bought it. Why is this problem?
  • Why does the last percentage of my iphone battery takes so long to charge? I have noticed that the very first percentages (1-20) of the iphone battery charges very quickly, but when it comes to the last percentage (99-100) it takes like 15 minutes to charge!
  • Why iphone is not showing accurate battery percentage? When i slept tonight it was 60 percent, i got up in morning its still 60 percent, i plugged in charger, suddenly it became 63 percent, why? Please tell if i discharge it completely & recharge to 100 percent wil it help to calibrate? Or factory restore is must to calibrate? Please you know factory reset means all my apps will be deleted, what to do?
  • Why battery percentage indicator in iphone is not showing accurate battery? Let its being charged, let it reached 97 percent, it will still showing charging, but if i off/on it, it will show 100 percent, and it shuts off when it reaches 4 percent, please tell what's problem? and as above i said, if i go to "usage" it will show time charged last time:0 mins standby:0mins but at top right its 99percent and is showing charging?