If you've got an iPhone 17, a Google Pixel 10 Pro or a Galaxy S25 Ultra, you won't need to worry about the age of your battery for at least a few years. But batteries do age over time so if you have a much older iPhone or an old Android phone, you may well find that your battery no longer gives you the same battery life it did when it was new. But having an old, worn-out battery doesn't mean buying an altogether new phone; it's surprisingly simple to just replace the battery. 

Apple has its own do-it-yourself repair program, but even if you don't use that, you can replace your iPhone's battery yourself at home. With affordable third-party components and various tools available to buy, you can open up your iPhone and swap out that old, worn out battery -- or replace a broken screen -- often for less money than having a company do it for you. 

I did exactly that, replacing the old battery of a well-used iPhone 6 to give it a new lease on life. I was pleased to find the phone on eBay for only £75 (about $100 or AU$140) back in 2020. That's a lot less than a new iPhone 17 Pro, but unfortunately the battery had aged to the point where the software had to artificially throttle the performance to stop it from shutting down. Instead of casting off the phone and getting buyer's remorse, I decided to purchase a replacement battery and tools from iFixit and have a go at changing out the battery myself.

It took a little over an hour, but I was able to safely swap out the battery and get the iPhone 6 running perfectly again. I'm not giving step-by-step instructions here -- head to iFixit and grab a kit if that's what you're after -- but I do want to describe my experience, including how easy the process was, and hopefully answer some of the questions you may have if you also need a new battery.

If you have a more recent model (an iPhone 12 or newer), then make sure to first check Apple's new repair options and see if you'd be able to put in a replacement with parts directly from the company. 

Note that any maintenance you do on your own devices is entirely at your own risk.

To get more about iPhones, check out everything Apple announced at WWDC 2025.

1. Why would you need to replace an iPhone battery?

Batteries age over time, and considering that the iPhone 6 was released years ago, it's no surprise that the one I bought wasn't running in prime condition. One time, the phone unexpectedly restarted while in use, and it flashed a warning that read, "This iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power. Performance management has been applied to help prevent this from happening again." Even the phone itself knew it had a bum battery.

In short, a phone's performance can be throttled if it can no longer cope with power demands. There is the option to turn throttling off, but this will result in more frequent crashes. Neither situation is ideal, so a battery replacement seemed like a smart way forward for me, since it wasn't my main phone and I was willing to take the risks. 

2. How much does a replacement iPhone battery cost?

The problem with my situation specifically was that I bought the phone for so little in the first place that spending more money on a battery replacement service negated some of those initial savings. Apple's replacement service costs £49 ($49), which is more than half what I paid for the iPhone 6 I bought. As I was in the middle of a coronavirus lockdown when I attempted this, I wasn't able to get to an Apple store to take it in, and sending it in through the mail would bring the total cost to around £56 (about $75 or AU$105).

iFixit, however, sells a DIY replacement pack for £35 (including postage to my home in Scotland). It costs $30 in the US, and with shipping costs that comes to about $38. It's not a huge saving over Apple's replacement, but every little bit helps. It also means you will still have the tools you need should you want to do this again in the future. All you'd need to buy next time is the battery.

3. What comes in the iFixit battery fix kit?

iFixit's kit comes with a third-party replacement battery that is not from Apple, since Apple does not sell its parts separately for phones older than the iPhone 12. It also has all the tools needed to open the phone and remove the old battery. The only additional thing I needed was a hair dryer to heat up and remove the glue.

4. Does replacing a battery void your phone warranty? 

Opening up an iPhone will void the warranty, but if your battery is old enough to need replacing, odds are you're already out of the 12-month warranty period. 

5. Is it safe to replace your iPhone battery yourself? 

This one isn't so straightforward to answer. iFixit's guide gives very detailed instructions on the steps involved, but there were a couple of points that made me nervous. One step involved heating up the back of the phone with a hair dryer in order to loosen the glue holding the old battery in place. 

Specifically, it said to heat it to "slightly too warm to touch comfortably," which I found a little vague. Especially since that section also warned that "overheating the iPhone may ignite the battery." But how hot is too hot? What signs would I see if it was overheating? I couldn't find this information, and as such wasn't sure how close to overheating it I might be.

Shortly after, while trying to pry out the old battery, I accidentally ripped into what looked like the black wrapping around that battery. I was pretty sure that the battery itself wasn't punctured -- there was no smoke or hissing -- but I'd have felt a lot more comfortable if I had "emergency" instructions on hand about what to look out for and what to do if the battery did ignite. 

6. Can I replace my iPhone battery myself?

Up to a point I found I could, and I'm not the best at DIY. iFixit's instructions were easy to follow, and there were only seven internal screws to remove, which were easy to then put back. 

One thing I found confusing was that the instructions on iFixit's website end at the point where you remove the old battery. The only instruction in the conclusion was to follow the previous steps in reverse order. Admittedly, that wasn't particularly difficult, but I would have appreciated more guidance at that point. 

I ran into one other issue in the process: When I removed the screen, I cracked the screen protector that was in place. I noticed the hairline cracks and was worried that I'd damaged the display itself, but thankfully that was unharmed.

7. Is it worth replacing an iPhone battery?

It depends on the age and value of your phone. If, like me, you bought a cheap used iPhone and just want to get it back up to speed, then it could be a great way to breathe new life into old tech without spending a fortune. Bear in mind, though, that this wasn't going to be my main phone, nor did I buy it with my own money. For me, the risk was low. If I'd made a mistake and ruined the phone, it wouldn't have been a big problem. You'll need to consider whether you really can manage without the phone, and weigh your tolerance for other risks.

If you're using a more recent device, like an iPhone 14 or 15, for example, I'd just take it directly to Apple. The savings you'll get from doing it yourself aren't so great as to justify the potential cost of damaging a more valuable phone.

Watch this: Apple announces DIY repairs for iPhones and Macs

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