How to Fix MacBook Battery Draining Overnight

You close the lid at 80% and open it at 40%. Something stayed awake. This guide measures your drain, finds what woke the Mac, and removes the usual suspects one by one.

Measure the drain first#

A few percent overnight is normal. Guessing wastes time, so put a number on it.

What drains a sleeping Mac#

Step 1: Ask the Mac what is blocking sleep#

Open Terminal and run:

$ pmset -g assertions

Seeing caffeinate, a video call app, a browser tab playing media or a download manager here means that process is the reason your Mac stays up. Quit it before bed.

Step 2: Check your Battery and Lock Screen settings#

1. Open System Settings → Battery and look at Options.
2. Review any setting that says the Mac can wake for network access, and decide if you need it. A Mac that keeps dropping and rejoining Wi-Fi can also wake more often; see how to fix Wi-Fi disconnecting.
3. Check Lock Screen for how long the display stays on.
4. On Intel Macs, the Energy settings may still list Power Nap. Turn it off to test.

Apple silicon Macs sleep deeply and wake rarely. If yours loses a lot overnight, the cause is usually an accessory or an assertion.

Step 3: Disconnect things#

Before bed, unplug USB hubs, drives and dongles. Turn off Bluetooth for a night if you can. If the drain disappears, add devices back one at a time to find the guilty one.

Also check whether an iPhone or iPad is charging from your Mac. That alone can account for a large drop.

Find what woke your Mac#

The power log records every wake and what caused it. Run:

$ pmset -g log | grep -E 'Wake|DarkWake' | tail -n 20

You will see lines containing Wake or DarkWake with a reason. Typical reasons include EC.LidOpen (you opened the lid), Network, and PowerNap or maintenance. A long list of wakes through the night points at a scheduled task or a network trigger.

Step 4: Look at Activity Monitor#

1. Open Activity Monitor → Energy tab.
2. Sort by 12 hr Power (or Energy Impact on older versions).
3. An app near the top that you rarely use is a suspect. Update it, or remove it from Login Items under System Settings → General → Login Items & Extensions.

For a broader look at runaway processes, see our guide to fixing high CPU usage.

Step 5: Check battery health#

A worn battery loses charge faster and makes any drain look worse. In System Settings → Battery, check Battery Health, then enter your numbers in the battery health check. If maximum capacity is low, an overnight drain that looks serious may be more modest than it feels. If the Mac will not charge normally, see the charging checklist.

Frequently asked questions#

How much battery should a MacBook lose overnight?#

Apple does not publish an overnight figure. As a rule of thumb, a closed, sleeping MacBook should lose very little. Use the calculator above to see where yours falls.

Should I shut down at night?#

It is optional. A full shutdown removes the problem completely, and a restart each week also keeps things tidy. You do not need to shut down every night for battery health.

Does closing the lid always put the Mac to sleep?#

Usually. Connected displays, some accessories and the caffeinate command can change that. The assertions check above shows whether something overrode it.

Could heat be involved?#

Yes. A Mac in a bag with a task still running can get hot and drain fast. Read how to fix MacBook overheating if the case feels warm in the morning.