How To Calibrate iPhone Battery

The iPhone features remarkable battery life, however, not every user experiences peak performance. It is essential to calibrate the lithium-ion battery periodically. This article details the process for maintaining your iPhone’s battery, which will ensure more accurate battery metering. This method also applies to the iPad and iPod Touch, as well as most other devices with lithium-ion “smart” batteries.

Why Calibrate?

Lithium-ion batteries degrade as they age and undergo repeated charging and discharging cycles. Operating systems, such as iOS, track the battery’s operating range. Regardless of wear and age, battery tracking requires occasional adjustment. Battery calibration helps iOS re-calculate the range of battery life. One should calibrate the battery periodically (every 1 – 3 months) and after every major iOS update. If you upgrade iOS and notice diminished battery life, inaccurate battery metering or unexpected shutdowns, try calibrating the battery before anything else.

Battery University, an online authority on batteries of all types, recommends calibrating smart batteries:

The chemical battery representing the actual energy storage remains the master while the digital battery provides peripheral support by relying on the information obtained from charge and discharge cycles. But like all fine machines, precise settings begin to shift and need adjustment. The same happens with an SMBus battery that also require periodic calibration. The instructions for an Apple iPad reads: “For proper reporting of SoC, be sure to go through at least one full charge/discharge cycle per month.

It’s important not to confuse calibration with regular charging practices. Your iPhone’s battery will last longer if you charge your device often, before it gets down to 0%. Ideally, you should plug your device into a charger before it goes below 20%. These are ideals and not practical for most people. In real life, many people need a full day’s charge. With battery replacements from Apple as low as $49, it’s an easier solution than closely-managed charging. For those who love fiddling and want to keep their battery in optimal condition, please read “How To Extend iPhone Battery Lifespan”.

With every iOS update, new features are added, some of which affect battery life. Apple’s engineers often improve some aspects of battery life, while also introducing battery-intensive features, such as background updates. Allowing the battery to fully drain and recharge calibrates iOS to detect the full range of battery life. Some people are skeptical of this theory, and since few know the inner workings of iOS, it may sound superstitious. Research and experience have proven otherwise.

How To Calibrate the iPhone Battery

The first step is to drain the battery completely. This should be accomplished with normal use, but sometimes this may not be an option. After all, you don’t want to head off to work with 2% battery life left. Sometimes that 2% can last a few hours. It’s best to drain the battery when you can do without your device for several hours, perhaps before bedtime. If you still have a little charge left and it’s almost time to sleep, you can drain the battery more aggressively. To expedite battery drainage, turn on the flashlight, turn up the brightness, and play a video, preferably streaming over the Internet.

Once your device powers off due to insufficient battery charge, it’s best to leave it for some time. If possible, leave it overnight and don’t charge it until the following morning. This is not always an option, and if it’s too inconvenient, skip this step. Allowing the device to sit overnight will further drain the battery. You may notice that even when your iPhone runs out of juice and powers down, when you immediately plug it back in, you will see it at 2-3% charge. This is partly due to the fact that some battery life was remaining when it powered down. To keep your data safe, iOS has to power down before the battery is fully drained. Otherwise, it would shut off without being able to save its state to secondary storage.

Next, plug your iPhone into the charger. Keep it in the charger until it’s at least 100% charged. If possible, keep it in the charger longer. According to Apple, 100% means that you will get the expected battery life, but the device can charge beyond this.

So, here’s how things work: Apple does in fact display the iPad (and iPhone and iPod Touch) as 100 percent charged just before a device reaches a completely charged state. At that point, it will continue charging to 100 percent, then discharge a bit and charge back up to 100 percent, repeating that process until the device is unplugged.

Doing so allows devices to maintain an optimum charge, Apple VP Michael Tchao told AllThingsD today.

“That circuitry is designed so you can keep your device plugged in as long as you would like,” Tchao said. “It’s a great feature that’s always been in iOS.”

Keeping the device in the charger after it reaches 100% will ensure it is fully charged. Two additional hours should do it.

It is best to charge your iPhone when it is off. After you plug in the charger, your iPhone will automatically start up in a few minutes. When it is back online, simply hold down the sleep/wake button and slide your finger over the off switch. Your iPhone will charge faster when it is off. It will also generate less heat, which will extend overall battery life.

If you turn your iPhone off to charge, make sure to estimate how long it will take to charge beyond 100%. Three hours is a safe bet for an iPhone 11. My iPhone 6 will charge to 100% in three hours, but the extra two hours ensures that it is fully charged — beyond 100%.

Now that your device is fully charged, you should reset it. This is done by holding down the sleep/wake button (on the top of the device) and home button, until the Apple logo appears. If you have a newer iPhone, without a physical Home button, hold the volume up and sleep/wake button. Your device will boot up and is now reset. Remove the charging cable when your device is up and running.

Step By Step Battery Calibration

The following process is what I consider to be the gold standard of iPhone battery calibration. For some, it might not be possible to follow all of these steps. If you are an on-call professional or hopelessly addicted to your iPhone, you might not be able to turn off your iPhone overnight or even for a few hours. At the bare minimum, you need to drain the battery until the device shuts off, charge your iPhone to 100%, and reset it by holding down the sleep/wake and home buttons until you see the Apple logo.

1. Use your iPhone until it shuts off automatically. If it is near 0% battery life and you want to drain it faster, turn on the flashlight, turn up screen brightness all the way and play a video, preferably streaming from the Internet.

2. Let your iPhone sit overnight to drain the battery further.

3. Plug your iPhone in and wait for it to power up. Make sure to use the charger supplied by Apple or one that runs at the same wattage and amperage.

4. Hold down the sleep/wake button and swipe “slide to power off”.

5. Let your iPhone charge for at least 3 hours. Older iPhones should be charged for 5 hours. The charge progress indicator is not displayed while your iPhone is turned off.

6. With the charging cable still connected, press the sleep/wake button for about a second to start up your iPhone.

7. When the iPhone has booted up, hold down the sleep/wake and home buttons until you see the Apple logo. If you have a newer iPhone, without a physical Home button, hold the volume up and sleep/wake button.

8. When your iPhone is back online, remove the charging cable.

Addressing the Critics

Numerous critics of battery calibration have emerged. They post (often nasty) comments and there’s even a top-ranking article debunking battery calibration, specifically mentioning this Appledystopia article. Riddled with contradictions, confusion and conflation, their main argument is that completely draining a lithium-ion battery is harmful. This is partially true, but battery calibration is not done every day. Battery calibration is performed periodically, no more than once every one to three months.

Draining your iPhone’s battery isn’t that harmful. Most people do this quite often, in the process of using their iPhone throughout the day. It’s not optimal, but it will not totally destroy your battery. The benefit of calibration outweighs running your iPhone down to 0% once every few months. Your device will have a more accurate battery meter. With more accurate battery metering, there won’t be any unpleasant surprises, such as missing that important conference call because your iPhone went from 30% to 5% in 30 minutes.

On the opposite side, they argue that fully charging an iPhone also damages the battery. Apple already has technology in place to carefully manage the last 20% of the charging process. Once your battery charge progresses over 80%, the iPhone’s power IC reduces charge current. This is known as a trickle charge. Reducing the charge stresses the battery less than running at full current. This is all the more reason you need to calibrate your iPhone battery. Your iPhone relies on accurate battery metering to determine when the trickle charge starts. Calibration helps ensure that the iPhone’s smart battery is accurate.

Critics suggest that calibration, by running the battery between two extremes, will do more harm than good. Again, this is a process that’s done once every 1-3 months. Most people drain their iPhone battery from use. They charge their iPhone all the way. If you do this methodically and throw in a system reset, you’ve just calibrated your iPhone. There’s nothing mysterious or damaging about this process. Everything is done within normal operating parameters of the device. People run their battery from 0% to 100% every day, for years on end. The whole point of calibration is to have an accurate battery meter. Performing calibration periodically won’t diminish iPhone battery lifespan. In fact, you can get more life out of a failing battery with calibration. Calibration ensures that processes such as trickle charging are more precise, as they rely on accurate battery statistics. Read the comments — they’re testimonials to battery calibration.

Critics of this article don’t tell their readers to turn off their iPhones while charging. When an iPhone is on and plugged in, it generates more heat while charging, which will shorten the battery’s lifespan. Despite this fact, most people will leave their iPhone on while charging. They’ll even continue to use it, even when it’s warm to the touch. It’s easier and more convenient to do so, but it does harm the battery.

The Appledystopia battery calibration guide, however, recommends turning the iPhone off, which charges the battery with less heat than typical charging.  The battery also charges faster this way, as the device is no longer consuming power. The notion that calibration harms a battery is bunk. Everything is done within normal operating procedures. iPhone users run their battery down every day. They charge their device to 100% all the time. To label this behavior damaging is delusional. Appledystopia isn’t trying to alter the way you use your iPhone every day. This article is simply outlines a procedure to calibrate the iPhone’s battery meter. I feel sorry for the poor soul who’s suckered into using 60% of their battery range, so they can make their battery last for a few more weeks. Such people can’t see the forest for the trees!

Critics of this article contradict themselves. One one hand, they suggest that Apple successfully manages all aspects of battery charging, including calibration. They silently fixed this issue, according to some. Then, in their same article or comment, they contend that draining and fully charging the battery is incredibly harmful. Which one is it? Does Apple provide users with a device that’s harmful to fully charge and discharge? Or do they manage every aspect of charging, including calibration? The answers are a bit complex, but they’re not the polarized contradictions that my critics spew forth. It’s safe to fully charge and discharge your battery, but not optimal.

Apple devices, to date, still need battery calibration. This includes the new iPhone 11 line. Apple has not silently fixed this issue. It’s true that Apple has made advances in battery management, but their website neither condones nor dismisses battery calibration. In my research, I have found iPhone users who had their device batteries calibrated at the Apple Store.

Some brands of smartphone do not need to be calibrated. Google’s Pixel line doesn’t need calibration, and they specifically mention this on their battery care page. It’s unclear how they manage diminishing battery lifespan on their device. Critics of this article claim that Apple has done the same thing, but they won’t mention it. That’s a big assumption to make. They could easily report this self-calibrating feature on their battery management page.

It makes sense for them to remain silent about calibration. Most people will just go to the Apple Store and maybe purchase something while there. It makes their product seem inferior. They have made no indication whatsoever that battery calibration is part of iOS 13 or any new release. Battery calibration requires that the user run the battery down to 0% and back to 100%, to determine the full range. Apple may do this discretely if this behavior occurs. If that’s the case, however, users can still follow this guide to initiate calibration themselves. Some may always top off their iPhone and never run the full range. When Apple admits that battery calibration is no longer necessary, I will be the first to update this guide. Until then, I’ll stick with the evidence at hand.

Critics take a cheap shot, claiming that I advocate turning on the flashlight, amplifying screen brightness and other measures to rapidly drain the battery. Yes, but only if you’re close to 0%. My critics didn’t miss that, yet their writing indicates that this is a long-running process. It’s their pathetic attempt to create a straw man. I never suggest turning every bell and whistle on and all the way up, in order to drain an iPhone from 100% to 0%. That’s an intentional deception put forth by my critics.

Battery calibration isn’t just backed up by anecdotes. Although many people have noticed significant improvement in battery meter accuracy, there’s proof beyond these accounts. Battery University provides some of the best information on lithium ion battery care. They wrote a whole article on how to calibrate a smart battery, which has been referenced by Appledystopia several times. Their guide is an excellent resource, however, it’s not specific to the iPhone.

If battery calibration works for you, or not, let Appledystopia know! Drop a comment below.

Make Your iPhone’s Battery Last Longer

A lot of people visit this site because their iPhone’s battery is shot. Calibration can help in some cases, but it is not a panacea. If calibration doesn’t improve your iPhone’s battery life, it may be time to replace the battery. Fortunately, you can prolong the lifespan of your new battery by following a few tips. For more information, please read “How To Extend iPhone Battery Lifespan”.

More Information

Many users are skeptical of this process and feel it is superstitious. I hope I have shed light on the reasons why you should calibrate your iPhone battery. If you doubt this article, take screenshots of your battery life (Settings > General > Usage) before and after conditioning the battery. I have found this process to work. Of course, your battery may drain at different rates depending on use. For more information and tips about lithium-ion batteries, please read this article.

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