Got the laptop, a MacBook Pro (2021, M1 Pro 16"), on March 29th, 2022.

Typical day: I leave home with 100% battery, go work in cafés or co-working spaces, and don't plug it unless it hits the 10% battery warning.

People have been saying the battery is great on it and so I got curious, wanting to find out how long it lasts and whether I should take a charger with me.

Here's what I've got:

  • On 2022-04-01: used it for close to 12 hours before getting the 10%-battery warning.
  • On 2022-04-11: used it for 8 hours before getting the 10%-battery warning.
  • On 2022-04-21: I used it for 6h16 before getting the 10%-battery warning.

This is in usage time, excluding any break, lunch, etc.

My work on it has been the same throughout the month: webdev work, of the same nature throughout the month, with the same software running. I use Docker, which is said to consume a lot of battery, but I was using it at the beginning of the month just the same.

My questions are:

  1. Does this look normal?
  2. How can I measure battery life more accurately? (via software, instead of my taking notes.)

1 Answer 1


1. Does this look normal?

Apps like Coconut Battery provide detailed information about the state of your battery - particularly the current percentage of 'Design capacity' e.g. how much it can charge compared to it's original or intended size.
They also keep a history log of your battery's cycles (though not the discharge time).

This should, at the least, give you sufficient grounds to ascertain whether your battery is in 'good health', or not.

Assuming the battery is in good health, then Yes, the time you get is 'normal' -- for your usage. There could be a runaway process, or other software inefficiencies, of course. Different or updated software may provide longer work time.

2. How can I measure battery life more accurately?

You may know the old XKCD cartoon about estimating the time left to copy files:

enter image description here

Any attempt to measure your battery life is at best an estimate, because no one knows exactly how much processing the computer is going to do in the future. They're just averaging what you've done so far and extrapolating.

As a web developer, you'll apreciate that websites like Facebook are going to use much more energy than a simple HTML page. So your dev work will similarly be variable, and not consistent. There may also be underlying, scheduled tasks that the OS might start doing.

You can use Activity Monitor's Energy panel to see what tasks are using the most CPU (and how much). You can also see how much total CPU is being used.

enter image description here

There is an estimate of time there -- Apple removed the time estimate from the menulet (likely because people would get upset when the estimate didn't hold up.)

enter image description here

Note that the "Time on Battery" includes Sleep. I'll be very surprised to get over 15 hours, if I actually do some work...!

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