MacBook Air M2 Battery capacity decreasing fast

It does seem a bit excessive, but the battery is functioning normally, which means Apple will not replace it even if you asked and offered to pay them the $200 yourself.

There is nothing wrong with your utilization. Most likely, the battery's maximum capacity will settle within a range of a few percent. It may fluctuate up or down a percent or two between charge cycles, but the long term trend is down.

In any event you can't do anything about it unless it diminishes below 80% at which point you can decide whether it's worthwhile to replace it or not. That may be years from now. Until then familiarize yourself with the following:

Batteries - Apple

Batteries - Maximizing Performance - Apple

I also recommend reading Lawrence Finch's User Tip When to charge your iPhone or iPad - Apple Community.

As he writes,

"While this tip is specifically for iOS devices, the same principles apply to all other Apple devices (watches, AirPods, MacBooks) as well as most other manufacturer’s products that have Lithium chemistry batteries."

Rechargeable batteries are by nature unpredictable in terms of longevity. Sometimes they lose capacity slowly from day one and then will start a faster capacity loss later in life. Others can lose capacity quickly in terms of first year (around 10% or so) and then remain at that capacity level for years before slowly losing capacity. It is just the nature of the beast.

So, is yours unusual? it likely may not be but if you notice it to quickly approach 80% there is a problem. But as stated, Apple or its authorized service providers won't replace it until it is under 80%.

In the meantime, as long as you have sufficient working time to serve your needs when it is on battery, I would not be concerned until that is no longer the case.

My mid-2010 17” MacBook Pro battery dropped from 100% to 88% over the first 18 months. Then it stayed between 85-88% for ~800 cycles over ~7 years.

Apple’s threshold for replacement is 80% health. If it falls below that, make a service appointment.

Same answer. Still normal... until it isn't. If and when its capacity diminishes below 80%, contact Apple. You can certainly contact them before then if you wish, but the ultimate decision remains theirs.

For what it's worth I don't think it's normal, but what I think doesn't matter. That's for Apple to decide.

Yes. I understand your concern, but it's still normal.

Amiko_ wrote:

10 days passed and it is now on 80%

At 79%, Apple will take action. Sounds like you won’t have long to wait.