How to cap your phone's charging at 80% (and if it's worth it)

What you need: an iPhone 15 or newer on iOS 26 or iOS 27, a Samsung Galaxy on One UI 6.1 or later (verified on One UI 9), or a Pixel 6 or newer on Android 15 or later (verified on Android 16). No extra apps, no jailbreak, no root. Setup takes about two minutes, and after that the phone does the work on its own.

Why bother limiting the charge at all

Lithium-ion cells age faster when they sit at a high state of charge for long stretches, which is exactly what happens every night your phone sits on the charger at 100% for eight hours. Capping charging at 80% or so is meant to reduce that stress. Apple, Samsung and Google have all built a version of this into their phones, they just hide it in slightly different places and call it different things.

The timing here is good, because MacRumors just published the third year of an actual long-term test on this exact question, and the numbers are worth looking at before you decide whether to bother. More on that below.

How to set a charge limit on an iPhone (iOS 27)

Apple’s version lives in the same spot it’s been in since iOS 17, and it still works the same way in the current iOS 27.0.1.

Open the Settings app.
Tap Battery, then tap Charging.
Choose a charge limit between 80 percent and 100 percent in 5 percent increments.

When the charge limit is set to 100 percent, Optimized Battery Charging is available instead, which delays the final stretch to 100% based on your routine rather than blocking it outright. If you pick a lower number, the iPhone charges to within a few percentage points of your chosen limit and stops, resuming only once the level drops more than 5 percent while still plugged in.

Need a full charge for a trip? Tap Allow Until Tomorrow to temporarily override the limit, and it returns to your set percentage at 6:00 a.m. the next day. If you’re on iOS 26.4 or later, there’s a faster route too: open the Shortcuts app, tap the plus button, search for Set Battery Charge Limit, and add it to your build. The default is 80 percent, and you can tap to change it to 85, 90, 95 or 100. Handy if you want a Home Screen or Action Button toggle instead of digging into Settings every time.

How to set a charge limit on Samsung Galaxy (One UI 9)

Samsung’s current software, One UI 9 based on Android 17, has rolled out across the Galaxy S24, S25, S26 and foldable lines through September and October 2026. The feature itself has existed since One UI 6.1, but it keeps getting more granular.

Open Settings and tap Battery.
Go to Battery protection.
Turn on the Battery protection toggle at the top.
Choose between Basic (stops at 100%, waits until it drops to 95% to resume), Adaptive (pauses at 80% while you sleep and finishes charging right before you wake up), or Maximum (hard caps the charge at 80%).

Picking Maximum gives you the firmest cap. You can then drag the slider at the bottom to set a desired charging limit between 80 and 95 percent, so if 80% feels too restrictive for your daily habits, 90% is a reasonable middle ground. Once it’s active, don’t be surprised by a lock screen notice: a “Charging stopped to protect battery” message appears, along with a shield icon in the battery indicator. That’s the feature doing exactly what you asked, not a fault.

How to set a charge limit on a Pixel (Android 16)

Google’s take is newer and lives under a menu called Charging optimization. On a Google Pixel phone, it is found at Settings > Battery > Charging optimization, where you can pick one of two modes: Adaptive Charging and Limit to 80 percent.

Open Settings and tap Battery.
Tap Charging optimization (on some Pixels running Android 16, this now sits inside Battery Health).
Choose Limit to 80% for a hard cap, or Adaptive Charging if you’d rather it learn your wake-up time.

The Limit to 80% option stops charging once the battery reaches 80 percent, and a shield icon appears next to the battery in the status bar to show the phone is done charging. Adaptive Charging works differently: it keeps charging to 100% but times the final stretch so your phone isn’t sitting at full charge for long, since that can strain the battery over time. Newer Pixels running Android 16 also show more context around this decision: tapping Battery Health lets you view your battery’s current capacity alongside tips on how to extend your battery’s lifespan based on your usage, with the same Adaptive Charging and 80% toggles sitting right there.

What three years of real data actually show

This is where it gets interesting. MacRumors’ Juli Clover has run the same experiment since the iPhone 15 Pro Max launched in 2023: keep the charge limit at 80% and track battery health every year. The latest results, published this week, cover three separate phones across three years:

iPhone Pro Max max battery capacity by time on an 80% charge limit

iPhone 15 Pro Max after 36 months sits at 88% maximum capacity with 369 cycles. The iPhone 16 Pro Max after 24 months is at 93% with 343 cycles. The iPhone 17 Pro Max after 12 months is at 97% with 277 cycles. That’s a reasonably clean degradation curve, and nothing alarming for phones racking up hundreds of charge cycles.

The more useful comparison is against phones that never used the limit at all. Back in the first year of the test, Clover’s limited iPhone 15 Pro Max maintained 94% battery capacity after 299 charge cycles, compared to 87% to 90% capacity for colleagues’ iPhones without the limit on the same model.

iPhone 15 Pro Max battery health after one year: charge limit vs none

So the gap is real, but it’s modest: a handful of percentage points of battery health after a year, not a dramatic difference. Apple itself frames the occasional overshoot as intentional rather than a bug: the phone will sometimes charge past your limit anyway because the iPhone may occasionally charge all the way to 100 percent, which Apple says helps maintain accurate estimates of the battery’s state of charge.

Common problems and how to fix them

Phone	Problem	Fix
iPhone	Charge Limit option is missing from Battery settings	Only the iPhone 15 and 16 series support this feature natively; update to the latest iOS build and confirm your model is on the supported list
iPhone	Charges past 80% anyway	Expected behaviour: Apple occasionally charges beyond the limit, even to 100%, to maintain accurate battery state-of-charge estimates
Samsung	Battery protection toggle does nothing when tapped	Don’t tap the switch directly; tap the text next to it to open the full settings page, then enable the toggle on that screen
Samsung	Phone always shows “Charging stopped to protect battery”	You’re in Maximum mode working as intended; switch to Adaptive or Basic in Battery protection if you want more daily capacity
Pixel	Adaptive Charging never seems to activate	The feature needs about 14 days to learn your charging habits, and won’t turn on if your routine varies, like when you travel
Any phone	Need a full charge for a trip or long day out	iPhone: tap Allow Until Tomorrow. Samsung: switch to Basic mode temporarily. Pixel: toggle off Limit to 80%

What this means for you

If you replace your phone every year or two, don’t bother. The battery health difference the data shows is small, and you’ll spend more time annoyed by a phone that runs out of charge on long days than you’ll gain in battery longevity.

If you keep phones for three years or more, it’s worth turning on. The three-year iPhone data above shows a meaningfully healthier battery at the 88% to 97% range rather than dropping into the low 80s, which is usually when people start noticing their phone struggling to make it through a day.

Pick the mode that matches your life rather than defaulting straight to the hardest cap. Samsung’s Adaptive mode and Pixel’s Adaptive Charging both aim for a full battery by the time you actually wake up, which gets you most of the longevity benefit without the inconvenience of a phone stuck at 80% all morning. Save the hard 80% cap for phones that mostly sit on a desk charger rather than travel with you all day.

How to cap your phone’s charging at 80% (and if it’s worth it)