Why does my iPhone stop charging before 100% and drain quickly?
Answer
This is often caused by a charge limit or Optimized Battery Charging setting, a weak or slow charger, heat, or a power-hungry app—not always a failing battery. Check Battery settings and charger first, then Battery Health if the problem continues.
Before you start: stop right away if…
- Stop using a cable or charger that feels damaged, smells burnt, or gets unusually hot.
Follow these steps
Check Battery usage and Low Power Mode
Go to Settings > Battery. Review which apps used the most power since the last charge. Turn on Low Power Mode temporarily if you need the phone to last longer while you troubleshoot.
You should see: You can see whether one app or feature is draining the battery unusually fast.
Review Battery Health and charging limits
Open Settings > Battery > Battery Health & Charging (wording can vary by iOS). Check Optimized Battery Charging and any Charge Limit. If a limit below 100% is set, raise it or turn the limit off if you need a full charge.
You should see: You know whether the phone is intentionally stopping early because of a limit or optimization feature.
Restart and charge at room temperature
Restart the iPhone, then charge it with a wall adapter in a normal room-temperature place. Avoid charging under pillows or in direct sun.
You should see: Charging progresses more steadily without heat warnings.
Retest with a known-good cable and adapter
Try a different USB-C or Lightning cable and a wall adapter rated for iPhone charging. Avoid charging only from a computer USB port for this test.
You should see: The battery percentage climbs past the point where it previously stalled.
Check Maximum Capacity if drain continues
In Battery Health, note Maximum Capacity. If it is significantly reduced or the phone suggests service, contact Apple Support or an authorized provider.
You should see: You either see a healthy capacity reading or a clear service recommendation.
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Extra tips
What to look for: Settings > Battery details, Optimized Battery Charging or Charge Limit below 100%, a Slow Charger notice, and high battery use by one app.
Before you change anything: Note your iPhone model and approximate iOS version. Have the Apple or MFi-certified cable and wall adapter you normally use nearby. Avoid third-party "battery repair" apps that ask for unusual permissions. Do not ignore extreme heat while charging.