How to Calibrate iPhone Battery: Step-by-Step

Here’s how to calibrate your iPhone battery and why it’s worth doing every so often. The benefits could surprise you!

Poor battery life is a common complaint among smartphone owners. It doesn’t matter whether you’re an iPhone or Android user; if you use your phone a lot during the day, the battery will be lucky to make it to sundown.

However, did you know that something as simple as calibrating your iPhone battery can help? Let’s take a closer look at how to calibrate an iPhone battery and why calibration is important. Once you do this, your iPhone can last longer and be ready when you need it.

Why You Should Calibrate Your iPhone Battery

Calibrating your iPhone’s battery (also referred to as resetting an iPhone’s battery) is a surprisingly important part of iPhone maintenance. Unfortunately, many people don’t realize its benefits, and even fewer take the time to perform the necessary steps.

Without a correctly calibrated battery, you’re likely to experience inaccurate and erratic battery percentage readings, quicker battery drain, and a shorter total lifespan for your battery. If your iPhone shuts down unexpectedly when your battery life percentage hits single digits, poor calibration is almost certainly to blame.

Many factors can cause a battery to become incorrectly calibrated. Software updates, background app refresh, new features, and even plain old day-to-day use can all cause discrepancies. And even if you haven’t noticed an incorrect calibration, performing the steps below will ensure all the ions in the battery are flowing, thus improving the battery’s peak performance.

While you shouldn’t need to calibrate regularly, it’s worth a try if you’ve had battery issues that other steps didn’t resolve.

If you do want to set a schedule, once every two to three months is a reasonable cadence for most people. You can also try it after a major iOS update if you notice your battery percentage behaving strangely — jumping from 40% to 15% in a matter of minutes, for instance, or dying at 20% when it used to last well into single digits.

One thing worth knowing: if you have an iPhone 11, iPhone 11 Pro, or iPhone 11 Pro Max running iOS 14.5 or later, Apple built in an automatic recalibration system for the battery health reporting on those specific models. You can check its status by going to Settings > Battery > Battery Health & Charging, where you’ll see a message if recalibration is still in progress. That automatic process can take a few weeks and runs during normal charge cycles, so there’s no need to do a manual calibration while it’s active.

Check Your Battery Health First

Go to Settings > Battery > Battery Health & Charging (on iPhone 14 or earlier) or Settings > Battery > Battery Health (on iPhone 15 or later) and look at the Maximum Capacity percentage. This number tells you how much charge your battery can hold compared to when it was brand new.

If that number is at or below 80%, calibration won’t do much for you — your battery has physically degraded to the point where it can’t hold the charge it once did, and no amount of drain-and-recharge cycling is going to fix that. Apple considers 80% the threshold where a battery should be serviced, and you’ll often see a “Service” message appear at that point. On iPhone 15 and later, you can also see your battery’s cycle count right on that same screen, which gives you a clearer picture of how hard the battery has been used. If you’re well above 80%, though, a calibration can absolutely help get the software’s reading back in sync with the battery’s actual capacity, and that’s when the steps below are worth your time.

Preparing to Calibrate Your iPhone Battery

Before starting the calibration process, you should take a few steps in preparation. They all revolve around disabling features and services, so as few tasks as possible draw power.

This will help lead to an accurate reading later in the process. After you’ve reset the battery, you can re-enable all of these options. It’s also worth ensuring you haven’t accidentally enabled Low Power Mode by going to Settings > Battery.

Disable Location Services

To disable location services on your iPhone, follow these steps:

1. Open the Settings app on your iPhone.
2. Scroll down and tap on Privacy & Security.
3. Tap Location Services at the top.
4. Now, toggle off Location Services.

Remember, you can use Location Services to track a lost iPhone, so make sure you don’t forget to re-enable this after you’re done calibrating.

Disable Background Refresh

Follow the instructions below to turn off the background app refresh feature on your iPhone:

1. Open the Settings app and tap General.
2. Tap Background App Refresh.
3. Tap on Background App Refresh a second time.
4. Choose the Off option.

Lower Your Screen Brightness

Here’s how to lower the screen brightness on an iPhone:

1. Open the Settings app.
2. Scroll down and select Display & Brightness.
3. Drag the Brightness slider all the way to the left.

Turn Off Automatic App Updates

Finally, to turn off automatic updates, follow these steps:

1. Open the Settings app.
2. Scroll down and tap on Apps.
3. Tap on App Store.
4. Under Automatic Downloads, toggle off App Updates.

Disable Optimized Battery Charging or Charge Limit

Go to Settings > Battery > Battery Health & Charging (iPhone 14 or earlier) or Settings > Battery > Charging (iPhone 15 or later) and temporarily disable your charging optimization. If you’re on an iPhone 15 or later, set the charge limit to 100% and turn off Optimized Battery Charging. If you’re on an iPhone 14 or earlier, toggle off Optimized Battery Charging.

This matters because Optimized Battery Charging is designed to pause at 80% and finish later based on your daily routine — which is great for everyday use, but it fights against what you’re trying to accomplish here. You need a full, uninterrupted charge from 0% to a true 100%, and that feature will get in the way. On iPhone 15 and later, if you’ve set a charge limit (say 80% or 85%), that will also prevent the battery from reaching a full charge during calibration. Set it to 100% for now. You can turn it back on when you’re done — and you should, because these features genuinely help your battery last longer over months and years of use.

How to Calibrate Your iPhone Battery

Now, you’re ready to calibrate the battery on your iPhone. Be warned that it takes quite a bit of patience; you’ll need to wait around for a couple of complete charge and drain cycles to finish.

Luckily, you don’t need any third-party tools or apps. Anything you see in the App Store promising to reset your iPhone’s battery is, at best, unnecessary and, at worst, a scam. iPhone battery calibration is easy to perform without extra help.

Step 1: Drain Your iPhone’s Battery

The first step is to completely drain your iPhone battery. You can do so during normal usage. If you want to speed up the process, you can play a long video on YouTube with the volume turned up to the maximum level.

Try to keep your iPhone in a room-temperature environment while you’re draining it. Running the battery down while the phone is sitting in direct sunlight, on a car dashboard, or on a wireless charger that generates heat can stress the battery in ways that go beyond what calibration is meant to do.

Step 2: Wait Three Hours

You may have noticed that your iPhone will automatically shut down even if the battery has a small percentage left. This process is by design; it gives the device a chance to save the current state of your apps so you don’t lose data.

It’s important to let the last embers of the battery life die away. The only way to do this is to wait. The longer you wait, the better, but you should wait at least three hours. If you have time, letting it sit overnight is preferable.

If you’re worried about damaging the battery by letting it sit dead for hours, there’s a built-in safeguard worth knowing about. When your iPhone shuts down at “0%,” it isn’t actually at zero — Apple reserves a small buffer of charge specifically to protect the battery from going completely flat, which is something lithium-ion batteries really don’t tolerate well. That reserve is there so the phone can sit powered off for a while without any real harm. Three to five hours is fine. Leaving it off for days or weeks, on the other hand, is not something you want to do.

Step 3: Charge Your iPhone

Now, it’s time to refill the battery. To ensure optimal performance, make sure you follow these tips:

• Use a wall socket rather than a computer to charge.
• Ideally, use an official Apple charger. At the very least, make sure you use a high-quality USB-C cable and not a cheap knockoff.
• Continue to charge for a couple of hours even after your phone shows the battery as 100 percent full. You need to ensure you squeeze in every drop of power to ensure the calibration works correctly.

Try not to use your iPhone at all while it’s charging during this step. Scrolling through apps or answering messages creates small charge-and-discharge micro-cycles that can throw off the reading you’re trying to establish. Plug it in, walk away, and let it do its thing.

Step 4: Drain Your iPhone

Now, you need to repeat the whole process a second time. It’s the same drill as before: completely drain the power out of your device. Either use it as you normally would or play videos on loop to move it along faster.

Step 5: Wait Another Three Hours

It’s getting repetitive by now but stick with it. Once again, you need to ensure you drain that last bit of battery power from your iPhone. Like before, the longer you can leave it, the better.

Step 6: Charge Your iPhone Again

To finish the process, you need to recharge your device. Follow the same guidelines as earlier, ensuring you let your phone continue charging for a couple of hours even after it’s full.

See also: Are YOU charging your iPhone correctly?

Finally, you need to re-enable the services and functions you disabled earlier. Turn Location Services, Background Refresh, and Automatic Updates back on and turn the screen brightness back up.

Don’t forget to turn Optimized Battery Charging (or your preferred charge limit) back on in Settings > Battery > Battery Health & Charging (iPhone 14 or earlier) or Settings > Battery > Charging (iPhone 15 or later). This is easy to overlook, and leaving it off means your battery will charge to 100% every single time, which over weeks and months adds unnecessary wear.

Once everything is re-enabled, do a quick restart of your iPhone to help the system fully register the new calibration data. On all iPhones running the current iOS — including iPhone SE models with a Home button — press and quickly release the Volume Up button, then press and quickly release Volume Down, then press and hold the Side button until you see the Apple logo.

And that’s it. Now, your iPhone battery has been recalibrated.

Other Battery-Saving iPhone Tips

Now that your battery is freshly calibrated, turn on Optimized Battery Charging if you haven’t already. Go to Settings > Battery > Battery Health & Charging (iPhone 14 or earlier) or Settings > Battery > Charging (iPhone 15 or later) and make sure it’s enabled. This feature learns your daily routine and delays charging past 80% until right before you typically pick up your phone — it’s one of the best things Apple has done for long-term battery health, and it works without you having to think about it. On iPhone 15 or later, you can also set a specific charge limit anywhere from 80% to 100% in 5% increments if you want even tighter control.

If recalibration hasn’t fixed your iPhone battery problems, it might be time to spend some money on a new battery. You can replace the battery yourself through Apple’s Self Service Repair program, which gives you access to genuine Apple parts, tools, and step-by-step manuals. Using genuine parts won’t void your warranty, though any damage you cause during the repair isn’t covered by Apple.

Therefore, it’s always better to make an Apple Store appointment at a Genius Bar and get it replaced with professional help. A new battery and the required labor aren’t as expensive as you might think.

If you’re still seeing strange battery behavior after calibrating and your Maximum Capacity is above 80%, the issue might be software-related rather than battery-related. A rogue app running in the background, a buggy iOS update, or even a corrupted system file can drain battery life in ways that look like a hardware problem but aren’t. Go to Settings > Battery and scroll down to check which apps have been using the most power over the previous day — you can also tap View All Battery Usage and select individual days going back about a week — sometimes the culprit is obvious once you look. If nothing stands out, contacting Apple Support directly (through the Support app or apple.com/support) is worth doing before you commit to a battery replacement, since they can run remote diagnostics that check things you can’t see on your own.