My iPhone 12 mini battery health is decreased after 2 months

Battery Health & Performance 

Your battery health is fine and is undergoing normal usage. iPhone batteries, like all rechargeable batteries, are consumable components that become less effective as they age. You should change out the battery once your Battery Health reaches below 80% which will take over 2 years to reach under normal usage. Until then enjoy your iPhone.

Here is some more reading on an iPhone battery and its performance ➔ iPhone Battery and Performance - Apple Support

Axel F.  

saikat164 wrote:

Can you please tell me your battery cycle? I have the same purchase date and I have 40 cycle and 99% Battery Health

Knowing someone else's battery health is worthless information. Unless you have all the same apps on your phone as the other person, all the same settings, and use your phone only in exactly the same places at exactly the same time and charge it exactly the same times, your battery usage will be different.

Your battery health will decline. It will do so, on average between 1 and 2 percent a month. There's nothing you can do to change that. So, don't waste your time and energy overthinking this. You bought a phone, not a really expensive battery meter (as someone else here likes to point out.)

See here:

When to charge your iPhone or iPad - Apple Community

saikat164 wrote:

Can you please tell me your battery cycle? I have the same purchase date and I have 40 cycle and 99% Battery Health

On average it will drop 1% for every 25 full charge cycles. Batteries are consumables; they lose a little capacity every time they are discharged, then recharged. On average this works out to about a 1% loss for every 25 “full charge cycles”. As one example, if you charge the phone overnight, every night (and that is what you should do; it is a best practice), it starts the day at 100%. If it drops to 20% by the end of the day before you charge it again overnight that counts as 0.8 full charge cycles (20% to 100%), or about 24 full charge cycles per month of use. For this example your battery capacity will lose about 1% per month. Of course, if the end-of-day level is higher than 20% the capacity loss will be a little less, and if it is lower than 20%, or you charge it during the day, the capacity loss will be higher.

The other thing to keep in mind that a battery is a chemical device, and chemistry is generally pretty variable and uncertain, as well as being analog, not digital. Apple specs the battery capacity to remain above 80% for 500 full charge cycles, but that is a minimum requirement; there is no published maximum expected capacity. So sometimes batteries will perform much better than that minimum specification, and sometimes the change in maximum capacity won't be linear. 

That's normal, keeping in mind that the maximum capacity percentage is related to when the battery (not the iPhone) was new.

Start worrying when that value goes down close to 80%.

Regards

Giulio

Can you please tell me your battery cycle? I have the same purchase date and I have 40 cycle and 99% Battery Health