Battery acting weird? How to calibrate your phone and laptop

Jumping percentage displays, a suddenly empty smartphone, or unexpected switch-offs despite a remaining residual charge are typical everyday battery problems. These issues are often not caused by a defective battery, but by an incorrect assessment of actual charge level. This can usually be remedied by calibrating the battery. You can find out how this works here.

What does battery calibration mean?

Lithium-ion batteries normally lose capacity over time. However, the operating system cannot measure this state directly, but calculates it based on charging and discharging cycles. If these reference points become inaccurate, the percentage display will no longer be correct.

During calibration, the system re-learns when the battery is truly full or empty. This doesn’t improve the runtime itself, but ensures that the display provides realistic values again and that unexpected shutdowns occur less often.

How to recognize an incorrect battery display

Typical signs are abrupt jumps in the battery level or a smartphone that simply switches itself off when it’s got ten or fifteen percent left. A rapid drop immediately after disconnecting from the charger can also indicate an incorrect assessment.

It’s important to differentiate, though. If the battery lasts significantly shorter than before, this is usually a normal ageing process. In this case, calibration will not bring any noticeable improvement.

Calibrating the battery for iPhone and Android

Calibration works on the same principle for iPhones and Android smartphones. All you need is a charger and some time.

1. Fully charge the battery to 100 percent.
2. Use the smartphone until it switches itself off.
3. If possible, try switching it on again and continue to discharge it.
4. Once the device is completely discharged, charge it fully to 100 percent when switched off, then leave it connected for an additional 30 to 60 minutes.
5. Disconnect the device from the charger and restart it.

Note: Many smartphones automatically limit charging to 80 or 85 percent to protect the battery. This function must be deactivated briefly for successful calibration.

Once the calibration is complete, you should reactivate the charging limit as it significantly improves long-term battery health.

Does battery calibration also work on laptops?

Yes, the battery indicator on laptops can also become inaccurate over time. The principle is identical: fully charge the battery once, then fully discharge it, and finally charge it fully again.

Many devices have charging limits in the BIOS or in manufacturer tools. These should be deactivated before calibration and switched back on again afterwards. On MacBooks, this function is performed by battery status management in the system settings.

When it is better not to calibrate

Calibration is not a routine process. Each complete discharge puts a strain on the battery and can shorten its lifespan, so it’s not recommended without clear signs of an inaccurate charge display.

For everyday use, the following still applies: a charging range between around 20 and 80 percent is best for the battery. Calibration should only be reserved for specific problem cases, not for regular use.