How to Calibrate an iPhone

Readjust the motion sensors, Auto-Brightness, Home button, and battery

Calibrating the iPhone
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iPhones are prized for their reliability. However, some of their features can become less accurate or responsive over time, making it difficult to use certain apps. This guide explains what you can do to resolve such issues, covering the recalibration of screen brightness, the compass (and motion sensor, accelerometer, and gyroscope), the battery, and the Home button.

Note: It does not, however, explain how to recalibrate the touchscreen.

How to Calibrate iPhone Screen Brightness

Calibrating Auto-Brightness
You can calibrate the Auto-Brightness sensor by turning it off and then turning it on again in a dimly lit room.

Sometimes you might notice your iPhone's Auto-Brightness sensor isn't working properly, as indicated by the phone responding inappropriately to changes in lighting. Here's how you recalibrate it:

  1. Go to Settings
  2. Scroll down and tap Display & Brightness
  3. Swipe Auto-Brightness into the white/blank Off position
  4. Move to a dark/dimly lit room, and then manually turn the Brightness all the way down, so the screen is as dark as possible
  5. Swipe Auto-Brightness into the green On position

How to Calibrate iPhone Motion Sensors/Compass

Calibrating the Compass
The Compass and motion sensors can be calibrated using the iPhone's Location Services.

There are a number of apps that make use of the iPhone's motion sensor, its accelerometer, and its compass; so, when any one of these stops working properly it can make life frustrating. Fortunately, these can both be recalibrated regularly by ensuring that your Location Services are switched on. Here's what you do if they aren't already on:

  1. Open Settings
  2. Scroll down and tap Privacy
  3. Tap Location Services
  4. Swipe the Location Services toggle switch into the green On position
  5. Scroll and down and tap System Services
  6. Swipe the Compass Calibration toggle switch into the green On position
  7. Swipe the Motion Calibration & Distance toggle switch into the green On position

That's it.

Note: Users with older versions of iOS may need to recalibrate the Compass and motion sensor by opening Compass and going through a little mini-game that requires you to roll a red ball around a circle.

Calibrating the gyroscope via app
Certain apps let you calibrate the gyroscope, accelerometer or motion sensors directly.

Also, there's an alternative way to calibrate these tools. With certain apps, you can go to its Settings and calibrate the relevant tool directly (as shown for the gyroscope in the example above).

How to Calibrate iPhone Home Button

Recalibrating the Home button
Recalibrating the Home button involves opening any app and holding the Home button and Wake/Sleep simultaneously.

Users with an iPhone model earlier than the iPhone 7 may find that their Home button can get a tad unresponsive at times. If this ever happens to you, here's what you can do to recalibrate it:

  1. Open any app (the example above uses the Clock app)
  2. Press and hold the Sleep/Wake button until the "slide to power off" screen appears
  3. Press and hold the Home button until the power off screen disappears. This takes approximately 5-10 seconds.

How to Calibrate iPhone Battery

Charging the iPhone's battery
It's best to charge the iPhone while it's off when calibrating its battery. Chesnot/Getty Images

It might seem strange to say you can calibrate the iPhone's battery, but you can, at least in the sense of calibrating how the phone monitors and reports the percentage of remaining battery power. This is needed whenever the iPhone begins giving inaccurate percentages, either showing a low percentage when it ends up lasting an hour or two longer, or showing a healthy supply of battery power only to shut down suddenly.

  1. Fully discharge the phone, using up the battery power until it shuts off.
    1. Note: This can be sped up by using multiple apps at once, such as using the flashlight, or streaming media, etc.
  2. Leave the phone discharged and unplugged overnight in order to ensure the battery is completely drained.
  3. While the phone is still powered down, charge it for a couple of hours longer than is usually necessary to bring it to '100%' capacity.
  4. Reboot the phone, then perform a soft reset (aka warm reset).

The method for performing a soft reset varies with the particular iPhone model you have:

  • For models earlier than the iPhone 7 (e.g. iPhone SE, 6S, 6, 5S, 5, 4S, 4), you have to simultaneously hold the Sleep/Wake button and the Home button for around ten seconds
  • For the iPhone 7 and 7 Plus, you have to hold the Volume Down button and the Sleep/Wake button for about ten seconds again
  • For the iPhone X, 8, and 8 Plus, you have to press and release the Volume Up button, then press and release the Volume Down button, and then finally press and hold the Side button until the Apple logo appears

Once all of the above has been completed, your phone should be able to give a more accurate indication of its battery status, although if problems persist it may be necessary to replace the battery altogether.