01Why your iPhone stops charging at 80%
If your iPhone stops charging at 80%, iOS is doing it on purpose. Either a Charge Limit is set, Optimized Battery Charging is holding the last 20% until you usually unplug, or the battery is too warm and iOS is waiting for it to cool.
The pattern tells you which. Answer three quick questions:
A Charge Limit is switched on
Go to Settings > Battery > Charging and drag the slider to 100%. It takes effect on the current charge.
Optimized Battery Charging is working
It holds at 80% and finishes before your usual wake-up time. Leave it on, or turn it off under Settings > Battery > Battery Health & Charging.
The battery is too warm
iOS can limit charging above 80% until a warm battery cools. Get it out of the sun, take off a thick case and stop heavy apps.
Heat fixes| Cause | How it behaves | Where to change it |
|---|---|---|
| Charge Limit (iPhone 15 and later) | Stops at the same number every time: 80, 85, 90 or 95% | Settings > Battery > Charging |
| Optimized Battery Charging | Holds at 80% overnight, then finishes by your usual unplug time | iPhone 14 and earlier: Settings > Battery > Battery Health & Charging |
| Heat | Stalls around 80% or pauses at any level; may show Charging On Hold | Can't be switched off. Cool the phone |
| Clean Energy Charging (US only) | Delays charging when the local grid is dirtier | Same Battery settings screen as above |
02Change the Charge Limit on iPhone 15 and later
Starting with iPhone 15, Apple added a hard Charge Limit. Many people pick 80% during setup or after reading about battery health, then forget. It's the most common reason a newer iPhone parks at 80% every single time.
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Open Settings > Battery > Charging
This is the Charging screen, not Battery Health. You'll see a slider labeled Charge Limit.
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Drag the slider to 100%
The slider moves in 5% steps from 80% to 100%. Pick 100% for a full charge, or 90% as a middle ground that still eases wear.
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Check Optimized Battery Charging
With the limit at 100%, Optimized Battery Charging can still hold your phone at 80% overnight. If you need a full battery right now, switch it off on the same screen.
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Leave it plugged in
Charging carries on from wherever it stopped. No need to unplug or restart.
03Turn off Optimized Battery Charging on iPhone 14 and earlier
Older iPhones don't have a fixed limit. Instead, Optimized Battery Charging studies when you usually unplug, holds at 80% and tops up to 100% just before. Apple says it needs at least 14 days of your charging habits before it kicks in, so a new phone that suddenly starts doing this two weeks in is behaving normally.
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Open Settings > Battery > Battery Health & Charging
Optimized Battery Charging is a toggle near the bottom of this screen.
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Pick Turn Off Until Tomorrow for a one-off
Ideal before an early flight or a long day out. It switches itself back on the next day.
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Or tap the Lock Screen notification
While it's holding, a notification shows when the phone will be full. Touch and hold it, then tap Charge Now to finish immediately.
The feature only engages when it's confident about your routine. Shift workers and travelers often find it rarely holds at all, which is fine.
04When heat is holding it at 80%
Apple notes that when the battery is too warm, software may limit charging above 80% until it cools. The giveaway is inconsistency: it stops at 80 in the car on a hot afternoon but reaches 100% on your nightstand. Wireless pads, thick cases, sunshine and charging while gaming all push the temperature up.
Cool the phone, lock the screen and remove a bulky case, and it should resume within 10 to 15 minutes. If you also see a Charging On Hold alert, read our Charging On Hold guide. If the stall only happens on a wireless pad, the wireless charging fixes will help.
05Should you keep the 80% limit on?
For most people, yes, at least most of the time. Lithium-ion batteries age faster when they sit at full charge, especially when warm. Keeping the top 20% in reserve reduces that stress. The trade-off is simple: you start the day with a fifth less battery.
+Keep the limit
- Slower long-term battery wear
- Less time sitting at full charge overnight
- You rarely drop below 20% by bedtime anyway
- Easy to override on travel days
–Switch to 100%
- You often hit 20% before evening
- Long travel days or shifts with no outlet
- Older battery with reduced capacity
- You'd rather replace the battery than ration it
Our take: set 80% or 90% on a phone you plan to keep for years, and bump it to 100% the night before a big day. If 80% genuinely doesn't last, a pocket power bank or a faster charger at your desk solves it without giving up the battery protection. The 20-80 charging rule explains the reasoning, and you can check how worn your battery is in battery health.
A quick top-up at lunch or a snap-on bank in your bag covers the missing 20% without changing your settings.
Questions people ask
How do I get my iPhone to charge to 100%?
On iPhone 15 and later, go to Settings > Battery > Charging and set the Charge Limit to 100%. On iPhone 14 and earlier, go to Settings > Battery > Battery Health & Charging and turn off Optimized Battery Charging, or choose Turn Off Until Tomorrow.
Is it better to charge an iPhone to 80% or 100%?
Stopping at 80% is gentler on the battery over the long run because the cells spend less time at full charge. Charging to 100% is fine when you need the range. Many people keep a limit day to day and lift it before travel.
Why did my iPhone suddenly start stopping at 80%?
On an older iPhone, Optimized Battery Charging switches on after it has learned your routine, which takes at least 14 days. On iPhone 15 and later, check whether a Charge Limit was set. A heat wave or new thick case can also trigger it.
Does the 80% limit work with wireless chargers?
Yes. Charge Limit and Optimized Battery Charging apply to any charger, wired, MagSafe or Qi. Wireless pads also run warmer, so heat-related stalls near 80% are more common on them.
Is my battery broken if it won't go past 80%?
Almost never. Check the settings above first. If the limit is at 100%, Optimized Battery Charging is off, the phone is cool and it still stops, restart it and check battery health. A battery with a very low maximum capacity should be looked at by Apple.