Is It Safe to Charge an iPhone Overnight? Apple’s Answer
You can charge an iPhone overnight, and Apple says the reason is that the iPhone stops charging by itself once the battery is full.
Apple’s page on charging and maintaining the iPhone battery puts it this way: “it’s safe to keep your iPhone connected to a charger overnight.” The charging settings differ by model, and the steps below split into iPhone 15 and later, and iPhone 14 and earlier.
Does an iPhone stop charging when it is full?
Yes. Apple’s battery page says: “iPhone automatically stops charging when the battery is fully charged.”
Apple says charging every night is fine even when the battery has not been fully depleted. After a full charge, “Charging resumes automatically if your battery level drops below 95 percent.”
The iPhone also manages heat. Apple notes that a battery warms up as it charges, which can reduce its lifespan, and that the iPhone gradually reduces the charging current as the battery approaches full charge to reduce the effect of heat and prevent overheating.
Apple’s advice to unplug when it is possible
Apple’s advice: “When possible, unplug your iPhone after it has fully charged.” By default your iPhone uses Optimized Battery Charging, which Apple says reduces the time the iPhone spends fully charged and fully charges it just in time for you to use it.
Apple’s Optimized Battery Charging page describes the feature as designed to reduce wear on the battery and improve its lifespan by reducing the time the iPhone spends fully charged.
If you have an iPhone 15 or later
Apple’s steps for iPhone 15 models and later:
- Open the Settings app, then tap Battery.
- Tap Charging.
- Choose an option.
The option is a charge limit anywhere from 80 percent to 100 percent, in 5 percent steps. At a 100 percent limit, Optimized Battery Charging is available.
Apple’s page About Charge Limit and Optimized Battery Charging on iPhone says: “Your iPhone will charge to within a few percentage points of your chosen limit and then stop charging.”
Apple adds that with the limit set below 100 percent, the iPhone will occasionally charge to 100 percent so that its battery charge estimates stay accurate. For a chosen limit, Apple’s rule is “If the battery charge level drops more than 5 percent while connected to power, charging will resume, again charging to within a few points of your chosen limit.”
If you have an iPhone 14 or earlier
Apple’s steps for iPhone 14 models and earlier:
- Open the Settings app, then tap Battery.
- Tap Battery Health & Charging.
- Turn Optimized Battery Charging on or off.
Optimized Battery Charging is on by default when you set up your iPhone. Turning it off is your call, and Apple attaches this warning to the toggle: “Turning off charging optimizations can increase wear on your battery and reduce its lifespan.”
What Optimized Battery Charging does near 80 percent
With Optimized Battery Charging on, Apple says your iPhone “will delay charging past 80 percent in certain situations”. It activates only when the iPhone predicts it will stay on a charger for an extended period of time.
When it is active, a notification on the Lock Screen says when your iPhone will be fully charged. To get a full battery sooner, touch and hold the notification and then tap Charge Now.
Apple’s footnote on the Optimized Battery Charging page says the feature “needs at least 14 days to learn your charging habits, so it won’t engage before then.” The footnote adds that your iPhone “needs to experience at least 9 charges of 5 hours or more in a given location for Optimized Battery Charging to engage.”
Temperature limits for charging
On temperature, Apple says to avoid using or charging the iPhone in ambient temperatures higher than 95° F (35° C), which can permanently reduce battery lifespan. The ideal range Apple gives is 62° to 72° F (16° to 22° C).
Apple also says “Software might limit charging above 80 percent when the recommended battery temperatures are exceeded.” For more ways to look after the battery, see our guide How To Prolong iPhone Battery Lifespan: Avoid These 15 Things.
When the port or the battery is the problem
If the trouble is a charging port that will not hold the cable, see iPhone Charging Port Is Loose? Clean It, Then Go Wireless.
Apple’s battery page says: “All rechargeable batteries are consumable components that become less effective as they chemically age.” When yours has aged past what you can live with, iPhone Battery Replacement: Process And Cost covers the next step.
Frequently asked questions
Is it safe to charge an iPhone overnight?
Yes. Apple says the iPhone stops charging automatically when the battery is fully charged, which is why it calls keeping the iPhone connected to a charger overnight safe.
Can you overcharge an iPhone?
No. Apple’s battery page says: “iPhone automatically stops charging when the battery is fully charged, so it’s safe to keep your iPhone connected to a charger overnight.”
Why does my iPhone stop charging at 80 percent?
With Optimized Battery Charging on, Apple says your iPhone “will delay charging past 80 percent in certain situations”.
On an iPhone 15 or later, you can choose a charge limit between 80 percent and 100 percent.
Apple also says “Software might limit charging above 80 percent when the recommended battery temperatures are exceeded.”
Should I turn off Optimized Battery Charging?
That is your call. In its steps for iPhone 14 models and earlier, Apple’s page About Charge Limit and Optimized Battery Charging on iPhone says: “Turning off charging optimizations can increase wear on your battery and reduce its lifespan.”
On an iPhone 15 or later, the Charging screen also offers a charge limit between 80 percent and 100 percent.