iPhone 12 battery health says 88%

On average, Battery Health / Maximum Capacity declines at an average rate of about 1% a month. That's an average, not an absolute. Max Capacity might not decline at all for 2-3 months, then drop 3% the next month after that.

The iPhone 12 is approximately a year to a year and a half old using that general rule. If the phone was used all that much, it's possible that the phone might be 2 years or so old.

Replace the battery when it is down to 80%. With luck, you will have about a year to go on the current battery.

EmmyCJ Said:

"Battery: If I just bought an iPhone 12 and the battery health says 88% that means it’s been used right? A new iPhone should be at 100% battery capacity?"

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Battery Health:

Use this New and Out-Of the-Box?:

the Battery Health drops 2-3% right-out-of-the-box. So, if it is newly-purchased from Apple, then it may be a fault device. So, contact Apple Support, seeing what they can for you, interns of a new battery. Apple recommends you get a new battery, when the Battery Health reaches 80%.

Apple Contact Info:

• Contact Us - Choose Locations
• Proceed from there, as necessary
• Why the Wait: Phone calls are taking a bit to go through at the moment, due to lots of calls. With the Coronavirus Pandemic, many are at home at the moment, with much time on their hands to contact Apple. So, just stay on the line, and you will get through :)

Edit.....should read.....If the phone was not used all that much, it's possible that the phone might be around 2 years old or so.