Is it safe to charge your phone all the way to 100%?

Even though cameras performance, processor speed, and screen resolutions are always improving, we still often find ourselves charging our phones more often than we'd like. The act of charging a phone is about as simple as can be, but there's some debate regarding how long you should leave your handset plugged in.

For years, it's been said that letting your phone charge all the way to 100% will result in the battery degrading faster compared to unplugging once it reaches 80% or so.

Our forum users recently gave their two cents on this matter, and these are a few of the best responses so far.

i usually charge it when it gets down to about 40-50% and i let it charge up to about 90% and once a month i let it go down to 10% and then charge it up to full 100% yes i am a nerd. i know.


Battery experts mostly agree that for lithium batteries in general, it's ideal to charge up to 80%, and not let it drop much below 30-40% (Tesla also recommends that its car batteries not be charged beyond 80% for regular usage, and only charge to 100% for the occasional long trip). This is supposed to optimally prolong the battery's lifespan. Realistically, it's not easy to stop the phone from...

B. Diddy

According to Cadex (the world's largest manufacturer of battery testing equipment), who should know, 50% to 80% is ideal for lithium batteries. 40% to 80% isn't too bad. 15%? Might as well buy stock in a lithium battery manufacturer. Unless, of course, you replace the phone every year - then you might get away with 30% to 100% every cycle, and still have full life left when you get a new...


The optimal place is for it to be between 40% and 80% as much as possible. So, if you're going for optimal, then you're letting it get way too low and then charging it way too high. That said, that's only giving you 40% of the battery to work with, so you're charging more often, etc. More importantly, how long do you keep your phone? Solo per un anno o due ... basta usarlo come preferisci....


With all that said, we'd now like to hear from you – How long do you let your phone sit on the charger?

Join the conversation in the forums!

Joe Maring was a Senior Editor for Android Central between 2017 and 2021. You can reach him on Twitter at @JoeMaring1.

  • Gwhat da hell lmao, I'll just charge it to 100 because that's what quality assurance is all about.
  • 100% is what I charge to. I've seen plenty of people complain that their phone isn't charging to 100%. Now we are actually discussing whether or not it's good to charge to 100%?
  • Okay, sure maybe the maximum capacity of the battery would last longer if you stayed in the 40-80% range... But you're only using 40% of the battery's capacity then! So essentially you've traded reduced battery capacity "one day" for guaranteed reduced battery today. Congratulations.
  • Exactly, what's the point? What are you preserving at that point?
  • The capacity deterioration scales, so the more you're in the "sweet zone" and the fewer deep charge/discharge cycles you have, the more shallower cycles you are able to have. If you read the thread, there's a chart that gives an example. In the example, using more shallower cycles resulted in 9 months of additional use before any noticeable degradation was present.
  • Yeah, but you're artificially degrading your battery now (only using ~40% of max). It'll take a long time for the degradation from full charge cycles (which not many people discharge to 0%) top Getty got to 40% of max. Trade significant capacity now for slight gains later.
  • This is why we need replaceable battery!,
  • The 0-100% your phone tells you isn't the actual 0-100% of your battery. Manufacturers know the tradeoffs, so they calibrate what it tells you to the best trade between everyday capacity and long term degradation. So, yeah, just charge to 100%
  • I believe this is correct. SSD manufacturers also give less capacity to the user and hold some in reserve to compensate for cell degradation.
  • No, they put in extra because they know SSD cells go faulty.
    They put exactly what it says on the packaging. The formatting reduces the amount available to use. The rest is used by the OS.
  • You're half right, they don't put extra in to account for cell degradation though. But I didn't say that they didn't print the amount of space accurately on the box, I said they hold some in reserve, and that's correct. That's why it says an SSD is 240/250GB or 480/500GB (depending on manufacturer) rather than 256GB or 512GB which is what they actually contain. Formatting and the conversion from binary to decimal is utterly irrelevant in this instance, as is the install size of the operating system.
  • Why is the install size irrelevant? On something like the Pixel and I am assuming every Android phone on 8.0 and beyond, that is quite a chunk of space in regard to how Android updates are executed.
  • It's irrelevant because we're talking about the raw storage capacity of a SSD, how much space you've got left after you start installing software, OS or otherwise, does not make a difference. The Pixel and every other android phone also don't have SSDs inside them, so they're also irrelevant.
  • I've always wondered about this. It seems the answers are all over the place. Even from "experts". I charge it to 100 when I get home. It be between 40 to 50. Whatever.
  • I'm charging to 100% and to heck with it. I don't like to let it go below 50% and I'm happiest when it's full.
  • Who has the time to sit around and watch their phone charging so that they can stop it at 80%?
  • Of course it's safe. If it wasn't, you wouldn't be able to. I generally plug my phone in before I go to sleep, and charge it overnight to 100%. If I've used it very heavily I'll give it 20 or 30 minutes when it hits 5-15% to get me to 50-60%. Life is too short to micro manage your phone battery to the point where you keep it between 40-80%. It's not worth charging your phone 4 or 5 times a day to try and retain capacity you aren't using anyway. The phone is a tool that should make your life easier not give you anxiety. I don't need or deserve the added source of stress, and neither do you.
  • The whole 40/80 rule is stupid. I don't want to babysit my battery and I don't want to only have 40% to get me by for the day. You also don't get any accurate battery stats if you don't charge them to 100%. Few of us have our phones more than a year. Heck, I buy a new one almost monthly. I don't need the battery to last 3+ years.
  • Who exactly is the few of you? I'm pretty sure it's the other way round, most people keep their phones for 2 years minimum considering that's the average pay monthly time.
  • In every phone is a special chip designed to protect your battery from damage.
    Sure, if you charge it from flat to full the battery will develop conductive crystals that will degrade the battery eventually. This happens regardless of the amount of charge.
    It's not a fault persay as a unwanted side effect of lithium batteries. So to keep your battery life as long as possible, only discharge to say 50% then top it right back up again. If you discharge to say 10% or lower and then recharge to 80%, it'll still generate these crystals. It's this difference that causes it..
    Don't worry about it. Worry if you buy knock-offs or fakes.
    Far too many small independent phone shops are selling fakes. If you get 18 months from your battery, then that's pretty darn good.
  • Everything night it gets put on the charger and when I wake up it's a 100%. Not gonna change that.
  • This conversation would be utterly pointless if phones had removable batteries. First, it's more convenient and faster to go from 0-10% charge to 100% within seconds and you can DIY. Second, it's more cost-effective. A spare battery is $15-30. You can buy a truckload and not caring about battery degradation.
  • This is why I still find myself using my lg g5 lol. Extra battery on hand and convenient external charger for spare battery battery last me all day and then some with regular usage. Swapping it out takes a minute . And if battery did start to show signs of age. I just grab another for 10-15 bucks on Amazon and I'm back to square one
  • It's true that removable batteries would come in handy, but it would also mean the loss of few other great things of our present day smartphone. For instance, my Galaxy Note8. If it had a removable battery, then it wouldn't have that glossy, beautiful jetblack finish. Glass is so beautiful and premium, albeit brittle and fragile than plastic. It would also mean the loss of the IP68 rating the device boasts. Even if it still persists with some water resistance, it would be IP67 at max. Removable back would make the phone less fingerprinty though. But I really crave that look, and many others too. That's why OEMs stay with premium materials such as Glass and Ceramic instead of Plastic. It would also weaken the signals a bit(cause glass is better at transmission of signals). If they try an LG G5 like solution, it is still not enough to convince the buyers.
  • My note 8 is always in a case so I don't care much about the glossy black back. I do miss the days of removable batteries. It's pretty rare that my battery gets below 30% though as it sits in an iOttie wireless charging mount whenever I drive from location to location for work.
  • My old Casio G Zone had a removable battery and was "waterproof" as well. So, you can have both of the worlds. When it comes to design, phones can still look good with the removable plate on the back. The reason why OEMs won't go for it (make it look add feel good) is that it would cost them a bit more and it would add .X in thickness. Same with waterproofing - they can do it but it makes the design more complicated - more expensive to build. Every penny counts.
    Now, one of the "conspiratorial" aspects is knowing that battery degrade - lose capacity over certain # of charging cycles and after a year or so people will notice and at one point may be annoyed enough to replace the phone. It's commonly known as Planned Obsolescence :) So there are pros and cons. The way I use phones I would always prefer them with swappable batteries. I constantly stream content and use GPS and even a beast like Z Play needs to be charged in the car for awhile. So, after 6 months my battery lost a lot of capacity already. I don't know how bad it will get in a year.
  • Concur with all the replies to your post. My phones have always been in a case. No exception. Therefore I don't care much about the "premium" material, so to speak. Bottom line, OEMs kind of force the consumer's hand to upgrade/change phone after 1 year or 2 due to battery degradation. Dollars speak...for them!
  • According to the experts, the battery would degrade slowly if the battery is kept between 40% to 80%. But according to a report it will last the longest if its kept between 45% to 55%. Charging upto a lower% and again charging after minimal use is not my cup of tow. I usually leave my phone for charging until it reaches a healthy%(in between 80). I charge it when necessary.If I need to get out, then even if its 30% or 40%, I charge it. If I am at home, I charge it when my battery reaches about 15%. Already Note8 doesn't have excellent battery life, and if I fear battery degradation and don't charge it to max, I won't be able to get the use out of it.
  • Partially charging your phone won't help its battery life because they have a set lifespan. For example, let's say batteries have 100 full charges until they no longer hold a charge. If you only charge your phone half way, then you still only have 99.5 charges left. It's not that your battery degrades slower. You're just not using it to its full capacity. There is no reason not to fully charge it.
  • That's it. That's what I want the experts to say. Anyways, I charge my battery to max. I was just talking bout the statistics presented by the scientists.
  • Tech sites should stop giving this topic credibility. Batteries have a set lifespan. No matter how much or how little you charge your device, that number doesn't change. Sure, you might get a couple extra days, but you'll also always have a partially charged phone. Most consumers upgrade their phone before the battery gets to that point.
  • The people who actually make batteries say that charging it to 100 does reduce battery capacity faster. that's not in dispute. the battery wear of going from 80-100% is the same as the battery wear of going 20. That being said, there's still some bit of practicality that needs to be exercised here. in regular use where I'm at work, at home, just doing the normal day to day routine I go to roughly 80%. If I forget about it and it gets to 100%, I don't sweat it, and my world isn't going to end. But I work at a desk and can top it up at work so I don't have to worry about it being at 100% to start my day every day. But on days when I know I need the longevity, I charge it to 100% and don't worry about it. That's what the battery is there for, so I use it when I need it.
  • If 80% is the optimal level, why not calibrated it for so that 80% of capacity show as 100%. Anything beyond will be consider ad "overcharged" . Give user a warning or choice to overcharge too
  • I just keep mine on the charger all the time. When I'm away from my desk is the only time I even use the battery. Has worked for me for years doing this.
  • I'd be more concerned about using fast charge than charging to 100%. I charge wirelessly most of the time (5w), so I rarely fast charge. Only on the rare occasion that I need 30% quickly.
  • I don't know why these posts exist. All major new phones charge on cycles. Charge as much or as little. Every phone has multiple protections for overcharging and over heating. There is no reason to not charge to 100%, it's all based on outdated information.
  • I've seen conflicting reports about thisbas well as other things about batteries. Taking them all in I am left with two warnings. 1. Don't let the battery drain down to zero all the time and 2. Don't change it full all the time. I probably charge my phone to 💯 about half the time it is on a charger. My Pixel 2 XL gets me through a 10 hour day easily on 50%.
  • how do you stop it from charging when you plug it in before going to sleep? I'll keep charging mine to 100 and if the time comes that my battery is crap I'll just have it serviced and replace the battery.
  • I don't keep my phone long enough for it to matter. I change phones every 6-12 months, so I just charge to 100% overnight and plug in around 15-20% when I go to bed. Life's too short to worry about these minute details
  • This is why we need replaceable battery!
  • Yes, it's absolutely safe to charge to 100%. Good for the battery? No, but it's better than leaving it plugged in over night and KEEPING it at 100%. Mine does not stay long at 100% because I'll unplug it about 10 or 15 minutes after it gets full, or I'll use a power bank that disconnects when the phone is full. If course, it helps not having to charge the phone every day, so mine does not see 100% every day. For the record, 100% is 4.23 to 4.25 volts on Android devices, and 4.28 volts on iOS devices. This may be why iPhones typically show degraded battery performance after 9 months (that's based on 5 years of data), and most Androids begin to degrade after 12 months. I know, there are exceptions, and my 3 year old M8 still goes all day, but I'm not gonna bury my head in the sand and say the battery is the same as when new, lol. Quality control and device power management also play a part, and I've had some phones that degrade after a couple months. If you really want to get extreme with battery management, then install an app to alert you when the battery gets to 80% (like Battery Monitor), and set your low power mode to come on at 50%. That's too much work for me, but some may appreciate doing so.
  • I get sick of my phone way before I ever have battery's charged to 100% in my vehicle about 8 hours a day...been doing it since the existence of cell phones.
  • Keeping your phone plugged in overnight does ZERO damage. Again, these phones have protections at the wall, port, and battery level to prevent over charge/heat damage.
  • Who has time to micromanage this crap?
  • Exactly. I charge mine when it needs charging, and use it without worrying about long-term battery life. I have owned 20 or so phones over the years, and I have replaced a "non-removable" battery only once (an iPhone). By the time a battery needs replacing, I have already moved on to another device. If a person keeps the same phone for more than 3 years without replacing the battery, then long-term battery health is a concern. Otherwise, don't worry about it and enjoy the phone.
  • This
  • Accubattery. Great app. Lets you know when your phone has reached the desired charge range. I set mine to let me know when it's at 78%. Done. It's not that hard to manage the battery for the average office working type.
  • No way in hell I am going to sit around, OMG my phone is at to unplug now!! I swap every year anyway so who cares.
  • Mine stopped charging past 83% for some reason and won't go to 100% anymore.
  • I guess you will gain a little bit if you plan to keep your mid range phone for 5 years but if you are a high end device user you probably change device once a year or even more often and will never notice a difference
  • I'm not waking up in the middle of the night to take my phone off charger if it's at 100%. I'll do that in the morning and go on about my day.
  • If it is so important to stop charging at 80%, why is there no programmable chargers?
    It would be nice with a Samsung wireless charger that i can program to stop charging at 80% But i don´t care so much about this, will probably change phone before the battery slows down...
  • Just enjoy your phones....use it and charge it when you want. The best thing is not to discharge completely.
  • I treat my 1st Gen Moto X (2013) this way. After 3.5 years I noticed the battery not lasting as long as usual. 3 months later had a shop replace the battery. Yep, just enjoy the phone, & try not to go to 0%.
  • Um, what does the user manual say?
  • Who cares about battery degradation? I charge it whatever i like and i have no complaints (1169 cycles) and 81.6% battery capacity