Is rapid battery health decrease normal for MacBook Air M4?

daviti291 wrote:

Hello, I’m concerned about my MacBook Air M4 battery health. It was at 97% on September 10, 96% on September 11, 95% on September 13, and today, September 20, it dropped to 94%. Is it normal for battery health to decrease by 3% within 9 days?

Yes, that is normal because the battery capacity cannot be measured to better than 3-5%, so it can fluctuate in that measurement even though the state of health is not actually varying that much.

You will get a better context for this after your Mac is several years old. For instance, my 2019 Macbook Pro 16" showed 99.4% on 6/6/20, 98.2% on 7/12/20, 99.0% on 7/20/20, 96.0% on 9/18/20.

More recently it showed 82.5% on 7/16/26, 85.8% on 8/11/26, 86.1% on 9/3/26, and 85.8% on 9/20/26.

Your best approach is allow the Mac to manage the battery using battery health management and to connect the laptop to a charger whenever possible. This may result in the laptop stopping charging when it reaches ~ 80% but you can always then tell it to "charge to full" if you need it to be portable for a while with a full battery.

Thank you so much for the detailed explanation! I was really worried about the battery health dropping so quickly, but your explanation made me feel much better. I really appreciate you taking the time to explain it!