Why is my MacBook battery draining so fast?
Updated 15 November 2026
Usually one of four things: an app working in the background, the screen, a task macOS runs after an update, or heat. Here is how to tell which.
1. Find the app using the most energy
Open Activity Monitor (Applications › Utilities) and choose the Energy tab. Sort by Energy Impact: Apple describes it as a relative measure of an app's current energy use, not watts or a share of your battery. 12 hr Power averages the app's impact over the last 12 hours, or since startup. Compare both before blaming a single spike. Apple's guide to the Energy tab.
Common culprits: a browser with many tabs or a video playing in one, video calls, a game or 3D app, and apps stuck at full speed after a bug. Quit the app (or close its tabs) and watch the charge for ten minutes.
2. Check what macOS is doing in the background
After a macOS update, a migration or a big import, the Mac re-indexes and analyses files for hours. In Activity Monitor these show as mds_stores and mdworker (Spotlight), photoanalysisd (Photos), bird or cloudd (iCloud sync) and backupd (Time Machine). They finish on their own; leaving the Mac on power overnight lets them.
3. Lower the screen and turn on Low Power Mode
The display is often the single biggest user of power. Dim it a few steps and turn off keyboard backlight when you don't need it. In System Settings › Battery, set Low Power Mode to “Only on Battery”: the Mac runs a little slower and lasts noticeably longer.
4. Watch the heat
A hot MacBook uses more power for the same work, and heat ages the battery. Keep the vents clear, avoid soft surfaces and direct sun, and look for the app that keeps the processor busy (step 1).
5. Check the battery itself
If none of the above explains it, the battery may simply hold less charge than it did. Check its health and cycle count: a battery below about 80% of its original capacity runs out noticeably sooner.
How much drain is normal?
It depends on the Mac and the work. Light use on an Apple silicon MacBook typically costs a few percent an hour; video calls, builds or games cost several times that. The useful question isn't the number but whether it's normal for your Mac on a day like this one.
Quick answers
What is the most common cause of fast MacBook battery drain?
An app working hard in the background, most often a browser with many tabs or a video call. Activity Monitor's Energy tab, sorted by Energy Impact, shows which one.
Is it normal for a MacBook battery to drain faster after a macOS update?
Yes, for a day or two. After an update the Mac re-indexes files for Spotlight and Photos, which uses extra power. It settles on its own, faster if the Mac stays on the charger overnight.
Does screen brightness affect MacBook battery life?
Yes. The display is often the biggest single user of power, so lowering brightness a few steps noticeably extends battery life.