Calibrating a MacBook or MacBook Pro battery for best performance

Calibrating a MacBook or MacBook Pro battery

The battery has an internal microprocessor that provides an estimate of the amount of energy in the battery as it charges and discharges. The battery needs to be recalibrated from time to time to keep the onscreen battery time and percent display accurate and to keep the battery operating at maximum efficiency. You should perform this procedure when you first use your computer and then every few months after that.
Calibrate the battery in your MacBook or MacBook Pro every month or two to keep your battery functioning at its fullest capacity.

To calibrate the battery:

1. Plug in the MagSafe power adapter and fully charge the MacBook or MacBook Pro battery until the light on the MagSafe connector changes to green and the Battery icon in the menu bar indicates that the battery is fully charged.
2. Allow the battery to rest in the fully charged state for two hours or longer. You may use your computer during this time as long as the power adapter is plugged in.
3. Disconnect the power adapter with the computer on and start using it with battery power. When the battery's charge gets low, you'll see the low battery warning dialog on the screen.
4. Continue to keep your computer turned on until it goes to sleep. Save your work and close all applications when the battery's charge gets low and before the computer goes to sleep.
5. Turn off the computer or allow it to sleep for five hours or longer.
6. Reconnect the power adapter and leave it connected until the battery is fully charged. You may use your computer during this time.

Repeat the calibration process every two months or so to keep the battery fully functioning. If you use your MacBook or MacBook Pro infrequently, it's best to recalibrate the battery at least once a month.
If you purchased additional batteries, repeat the calibration process with those batteries as well.