If you check the power tab under System Information, you can find some battery health info that might be illuminating. For example, my newish MBP16:

  Charge Information:
  Charge Remaining (mAh): 8362
  Fully Charged: Yes
  Charging: No
  Full Charge Capacity (mAh): 8647
  Health Information:
  Cycle Count: 18
  Condition: Normal

Looking it up, specced full capacity is 8818 mAh, so I'm at 98% health right now--probably lost a point or two because I leave it constantly plugged in at work. Willing to bet yours is much lower.

There are a few apps out there that can do a better analysis too. CoconutBattery used to be a good one, no idea if it's still around, but they were common.

I suspect the original capacity must have some variance.

Almost certainly, yes. I didn't note the capacity out of the box, so that 98% from spec is a bit handwavy for sure.

That said, Apple's usually pretty good about shipping things erring over spec, and publishing the low side of the real range. It was probably at least the spec amount when I got it.

FruitJuice is a good app for this. https://imgur.com/dY0n6Uw

CoconutBattery is also good https://i.imgur.com/bv85ygJ.png

It even supports plugged-in iOS devices https://i.imgur.com/nSIJrar.png

https://www.coconut-flavour.com/coconutbattery/

Thanks for the tip! I've been looking for something up to date that wasn't part of a huge suite.

8246 mAh after 34 cycles on my 16" 2019 MBP. That's a lot worse than I expected.

What's the best way to slow battery degradation if I use it for 8-10 hours daily for work? Run MBP from an outlet and do full discharges once a week? Run MBP from the battery and recharge the battery when it depletes? Run MBP from the battery, but charge it only to 80%?

At this point, I think anything you do is going to not be better than what the system could automatically do for itself. Their change will basically give you that 80% bit.

There's something to be said for occasionally running the battery down to zero and charging it all the way back up, of course, but I wouldn't think of it as an effective regimen with current battery tech.

I'm also not sure how quickly it's expected to drop in capacity. IIRC, batteries drop a notch when they start getting used, plateau there for a while where it mostly depends on environment (try not to charge them when it's 110deg ambient, for example, overheating will kill a battery fast); then eventually drop again and start heading on down.

And, of course, all of this scales by how cold it currently is ambient because lithium batteries have reduced charging capacities cold (though I don't think it damages them permanently like heat does).

For all I know, 95% (roughly where you're at) is the expected amount once all factors are concerned I wouldn't worry too much. Maybe just get some comparative specs on MacRumors or with one of the utilities (some benchmark against everyone else iirc)

I am at 89% and with some programs I work the whole MacBook heats up due to high GPU and CPU usage. Do you think this will degrade it much faster?

Thanks for the advice

Yikes - I have the same, and with a cycle count of 41, I'm down to 94%.

I have a 2015 13" MacBook Pro, and I'm on 85% after 940 cycles (5560/6559mAh - I guess the battery was smaller back then). I most often run it on the charger, but fairly often run it on battery down to a low percentagr too.

Just another datapoint here for a 2019 16" MBP bought at launch: 8542/8587 mAh for ~99.5%.

I have 46 cycle count, I keep it at my desk plugged in at 100% the vast majority of the time.

I don't think that's how you calculate it. You measure the Full Charge Capacity against what it's originally rated at. (What I've seen online is that the original capacity is 8790)

In your case, that'd be 8587/8790, or 97.7%.

To elaborate, you can install Coconut Battery and it will show the percentage I'm describing under "Design Capacity"

What you describe does sound just like a battery that was almost always fully charged, and is about .. six? years old. You may want to try the “rumored to work” calibration process, or replace the battery after the latest OS update:

https://help.ifixit.com/article/265-battery-calibration

Which is essentially “set it never to sleep automatically, plug it in overnight, unplug it for 24 hours lid open and let it die and stay dead a while, charge it fully” without ever interrupting the charging process.

On a healthy battery this will slightly reduce capacity each time due to deep cycle so don’t go doing this if you’re not experiencing “shuts down at 42%“ problems!

Probably there’s build up inside the battery simply given its age, and it’s unable to provide a steady power output, which also makes the reading wrong.

I had a similar issue with a 2012 MBA, tried SMC and PRAM reset which worked intermittently and ultimately replaced the battery for about $60.

Same. Its in otherwise great condition. I wish it was as easy to replace the battery as ordering one and popping it in.