01Your phone can't overcharge
Charging your phone overnight is not bad for it. Every modern smartphone has a charge controller that stops pulling power once the battery is full, so leaving it plugged in for eight hours doesn't push more energy in than it can hold.
The "overcharging" worry dates back to older battery types and cheap chargers that didn't cut off. Lithium-ion phones work differently. At 100%, charging stops. As the battery drifts down a little overnight, the phone tops it up again in short bursts.
There is one small, real cost. A lithium battery ages slightly faster when it sits at 100% for hours, especially if it's warm. That's what the overnight settings below are for. They don't stop the phone charging; they just change when it finishes.
02The one setting to switch on tonight
All three big phone makers built in a feature that holds the battery around 80% for most of the night and finishes the charge shortly before you usually wake up. It's often on by default, but worth checking.
| Phone | Where to find it | What to pick |
|---|---|---|
| iPhone 15 and later | Settings > Battery > Charging | Optimized Battery Charging, or a Charge Limit from 80% to 100% |
| iPhone 14 and earlier | Settings > Battery > Battery Health & Charging | Optimized Battery Charging |
| Samsung Galaxy | Settings > Battery > Battery protection | Adaptive (holds overnight) or Maximum (stops at 80%) |
| Google Pixel | Settings > Battery > Battery health > Charging optimization | Adaptive charging, or Limit to 80% |
Optimized and adaptive modes learn your routine, so give them a couple of weeks. Apple says its feature needs at least 14 days of charging history. If your phone seems "stuck" at 80% in the morning, that's usually this feature or a cap working as designed. See iPhone stops charging at 80% if it bothers you.
Shift worker, or no fixed alarm? Adaptive features guess poorly when your routine changes every day, and may simply charge to 100% early. A fixed cap is the more predictable choice in that case: 80% on iPhone 15 and later, Maximum on a Galaxy, or Limit to 80% on a Pixel. Switch it off the night before a long day when you need every percent.
03Heat and bedding: the real overnight risk
The bigger issue isn't the battery chemistry. It's where the phone spends the night. A charging phone gives off warmth, and soft surfaces trap it.
- Under a pillow or blanket: heat has nowhere to go. That's the single worst spot, for the battery and for safety.
- On a mattress or duvet: fabric insulates the back of the phone. Use a nightstand instead. If the outlet is far from the bed, a longer cable beats balancing the phone on the covers.
- In a thick case on a wireless pad: wireless already makes more heat than a cable. A bulky case holds it in.
- Next to a heater or in a sunny window: the room temperature adds to the charging heat.
If the phone's back or screen is bulging, a case no longer sits flat, or a charger smells hot or is discolored, stop charging it overnight. Swollen lithium batteries are a fire risk. Have the phone checked by the manufacturer or an authorized repair shop.
04Bedside charging checklist
Not sure your charger is genuine? Our guide to spotting a fake charger lists the giveaways. Counterfeit bricks are the overnight risk most worth avoiding, because they often skip the protection circuits real ones have.
05Cable or wireless pad overnight?
Wired, low-wattage
- Least heat of any option
- A 20W USB-C charger is plenty overnight
- Cable wears at the plug over time
Magnetic wireless stand
- Drop it on and walk away
- Magnets keep the coils lined up, which limits heat
- Slightly warmer than a cable
Flat Qi pad
- Phone can slide off-center
- Off-center charging wastes power as heat
- Fine if you place it carefully
Fast charging overnight is pointless rather than harmful. You've got hours, so speed buys you nothing. If you want the details, is fast charging bad for your battery covers it, and our bedside charging setup guide shows a few tidy layouts.
Stands and docks keep the phone upright and off the bedding. A plain USB-C charger works just as well if you prefer a cable.
Questions people ask
Does charging overnight damage the battery?
Not in any serious way. The phone stops charging at 100%. Sitting full for hours adds a little extra wear, which optimized or adaptive charging reduces by holding at 80% until shortly before you wake up.
Is it safe to charge a phone under a pillow?
No. A pillow traps heat around a charging phone, which wears the battery and creates an avoidable fire risk. Charge on a nightstand or another hard surface with air around it.
Should I unplug my phone at 100%?
You don't need to. Once full, the phone stops drawing charging current. If you want to reduce wear, turn on your phone's optimized charging or an 80% limit instead of setting an alarm to unplug.
Is it OK to leave my phone on a wireless charger all night?
Yes, with a decent charger and a slim case. Keep it centered (a magnetic charger helps), on a hard surface, and turn on Silent so vibrations don't nudge it out of position.
Why does my phone stop at 80% overnight?
That's the optimized or adaptive charging feature at work. It holds at 80% and finishes before your usual wake-up time. If it never finishes, check whether a fixed 80% limit is switched on in your battery settings.
Can I charge my phone overnight with a fast charger?
Yes. The phone controls the speed and slows down as it fills. It's safe, just unnecessary overnight. A cooler, lower-wattage charger is a perfectly good choice for the nightstand.