MacBook Air M1 maximum capacity dropped to 95% after three weeks

A drop from 100% to 95% maximum capacity after three weeks and 13 additional cycles is worth keeping an eye on, but it does not, by itself, show that there is a problem with the battery.

Your M1 MacBook Air  has a maximum cycle count of 1,000. Apple says its batteries are designed to retain up to 80% of their original capacity at that point under normal conditions. 

Battery capacity also decreases with chemical aging, which is affected by factors such as temperature and charging patterns. Apple Support — About battery health management in Mac laptops with Apple silicon

Your cycle count has gone from 18 to 31, but that does not mean those 13 cycles caused a 5% physical loss of capacity. 

Apple does not publish an expected capacity percentage for a battery at 31 cycles, so the 95% figure cannot be judged from the cycle count alone.

Because this is a MacBook Air can can date back to 2020,  the battery's age and history are also relevant. 

Apple notes that the time between manufacture and first use can affect the reported capacity, and that macOS may recalibrate the maximum-capacity measurement after a software update. Apple Support — About battery health management in Mac laptops with Apple silicon

It would also be worth checking System Settings > General > About > Parts & Service. 

If macOS detects a previous repair, this can provide information about the repaired part and, where applicable, the service date. 

However, Apple says that the absence of this section does not by itself establish that the Mac has never been repaired. Apple Support — About Mac parts and service history

Finally, check System Settings > Battery > Battery Health. 

The more significant indication would be Service Recommended, rather than the 95% figure by itself. 

Apple says this means the battery's ability to hold charge is lower than when new or that it is not functioning normally. Apple Support — If you see battery “Service Recommended” on your Mac laptop

So, based on the information available, I would monitor it rather than draw a conclusion from the 95% reading alone. 

If the capacity continues to fall substantially over a short period, or macOS reports Service Recommended, the battery would be worth having assessed.

Apple Support — Determine battery cycle count for Mac laptops

Download Coconut Battery, a free tool (you can pay to get additional features).

Among the free features:

Select "This Mac"

It shows the Mac manufacture date.

Select Battery Info ...

It shows the battery manufacture date.

My Mac is a 2019 Macbook Pro 16". Its manufacture date is 2020-03-23. The battery manufacture date is 2020-02-20. It is an SMP battery. So my battery is the original battery that came with the Mac when brand new.

Look up this data with your Mac. If the battery manufacture date is AFTER the Mac manufacture date, then when you got this Mac used, its battery had been replaced. Most likely with a third party battery, and those are known to be of uncertain reliability. When you get a used Mac, the price is often low but you don't really know what you are getting or its history. Often used Macs are being sold because something is wrong with them. Hence I would only consider getting a used Mac from Apple (with a warranty) or from OWC (with a warranty).

So find out the pedigree of the battery you do have. Your hours and cycle numbers are very low for a device that is likely 3-6 years old, so I suspect the battery failed and was replaced before you bought it. If the previous owner knew they were selling it, they no doubt did not put in a battery of the highest quality/cost. Probably something cheap.

That said, dropping 5% in 3 weeks is not necessarily unusual. The battery capacity cannot be measured to better than 3-5% and it something goes down or up over a period of days to weeks.

Here is a plot of my battery capacity, the same battery mentioned above, the original Apple battery. It has gone down by 5% and up by 5% over periods of a few weeks. Since July 2026 it has INCREASED capacity by 4%.

Hi,

I think it's normal, though you should see capacity of battery after using your MacBook Air for a month or so. I think battery detector is not that accurate, so if battery capacity drop down around 75% or so after using your MacBook Air for a month or so, it's not normal.

87Sul wrote:

I bought a MacBook Air M1 three weeks ago, and the device was very clean and like new.

Like new ≠ new

If you're unhappy about it, return it and get your money back.

That machine is at least 2 1/2 years old and could be up to nearly 6 years old.

87Sul wrote:

I bought a MacBook Air M1 three weeks ago, and the device was very clean and like new.

In other words, you bought a used Mac. Correct? The very last M1 MBA ever to be manufactured is now two and a half years old. The oldest ones are now about six years old.

Never buy a used Mac.

If that Mac's original Apple battery had been replaced with an aftermarket one, it is extremely common for them to "cheat" in a manner such that the battery capacity will indicate 100% when in fact it's nowhere near that value. Of course this is all speculation since that Mac's history is unknown. Given the unknown factors involved you have no alternative than to continue to use it, and hope it continues to work.