Energy Impact

Open Activity Monitor and click the Energy tab. Sort by 12 hr Power to see which apps used the most energy over time, then sort by Energy Impact to see what is using energy now.

An app that appears near the top of both lists, while you are not actively using it, is a good candidate to quit or check for updates.

Apple calls Energy Impact a relative measure. It is useful for ranking apps, but you should not read it as a power draw or compare numbers between different Macs.

The Energy tab also shows App Nap, which tells you whether an app is currently napping, and Preventing Sleep, which tells you whether an app is keeping the Mac awake. On Macs with more than one graphics processor, a column shows whether the app requires the high performance GPU.

Apple's developer guide says Energy Impact is based on how efficiently an app is operating, and that several factors go into it, including CPU use, network activity and disk reads and writes. That is why two apps with the same % CPU can have very different scores.

Apple has not published the formula. Treat the number as a ranking on your own Mac, not as a measurement.

The live number and the 12 hour average answer different questions. Looking at both tells you whether an app is a real battery problem or a short burst.

• High now, low over 12 hours: a burst of work, such as a page loading or a file syncing. Usually nothing to do.
• Low now, high over 12 hours: the app did heavy work earlier. Think about what you used it for, such as a video call or an export.
• High in both, while you are not using it: this is the app draining your battery. Quit it, update it or change its settings.

1. Open Activity Monitor, click the Energy tab and sort by 12 hr Power.
2. For each app near the top that you do not need, save your work and quit it.
3. In web browsers, close tabs that play video, animate or refresh on their own.
4. Check the App Nap column. An app that never naps while hidden keeps working in the background.
5. Turn on Low Power Mode. Choose Apple menu > System Settings > Battery, then choose Low Power Mode under Energy Mode. Apple says it reduces energy use to increase battery life.
6. Keep macOS and your apps updated, since developers often fix energy problems in updates.

sudo powermetrics --samplers tasks --show-process-energy -n 1 takes one sample and prints an energy impact figure for each process. It asks for your administrator password and takes about five seconds, since that is its default sample length. It only reads data and changes nothing.

Apple's own manual for powermetrics warns that its power figures are estimates, useful for comparing apps on one Mac but not for comparing different Macs.