Where to find your iPhone's battery health information
Your iPhone stores a battery health report that you can read in about 30 seconds. Open Settings, then tap Battery, then Battery Health & Charging. You will see a percentage labeled Maximum Capacity — this is the number that matters most.
Maximum Capacity tells you how much charge your battery can hold right now compared to when it was brand new. A new iPhone shows 100%. As you use it, this number drops. If your iPhone shows 85%, the battery can hold 85% of the charge it originally could. This is normal wear, not a defect.
Below Maximum Capacity, you may also see Peak Performance Capability. This line tells you whether iOS has slowed down your phone to protect the battery from damage. Most people see "Your battery is in normal condition" here, which means your phone runs at full speed.
Key Takeaways
- Maximum Capacity in Settings > Battery > Battery Health & Charging shows what percentage of your battery's original charge it can still hold.
- A battery at 80% capacity is still healthy and normal for a phone that is one to two years old.
- Peak Performance Capability tells you whether iOS has reduced your phone's speed to protect an aging battery.
- If your battery drops below 80% within the first year, contact Apple because the battery may be defective.
What the Maximum Capacity percentage actually means
Think of Maximum Capacity like a gas tank that shrinks over time. A new iPhone battery is like a full-size tank. After 500 charge cycles (a cycle is draining the battery and charging it back up), the tank gets smaller. After 1,000 cycles, it is smaller still. This is chemistry, not a failure.
Apple designs iPhone batteries to keep 80% of their capacity after 1,000 full charge cycles. That means if you charge your phone once a day, you should see around 80% capacity after about three years. If you see 85% after one year, your battery is aging slower than expected — you are doing something right.
The percentage does not mean your phone will die at 20% battery. It means when you charge to 100%, you are only filling the tank to 80% of what it used to hold. Your phone still runs normally. The battery just does not last as long between charges.
When Peak Performance Capability matters
Peak Performance Capability is a safety feature. If your battery gets very old or damaged, it can suddenly lose the ability to deliver power quickly. This can cause your phone to shut down unexpectedly, even when the battery shows 20% charge remaining. To prevent this, iOS automatically reduces how fast your processor runs.
You will see one of three messages here. "Your battery is in normal condition" means your phone runs at full speed — this is what you want. "This iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power" means iOS has already slowed your phone down to prevent shutdowns. "This battery has significantly degraded" means the battery needs to be replaced soon.
If you see either of the last two messages and your phone feels slow, you have two choices: replace the battery through Apple, or accept the slower speed. Replacing the battery costs between $50 and $100 depending on your model. A new battery will restore full speed.
How to read your battery health if you have an older iPhone
iPhones running iOS 16.1 or older show battery health in a slightly different place. Open Settings, tap Battery, then Battery Health (not "Battery Health & Charging"). You will see the same Maximum Capacity percentage, but the Peak Performance section may be labeled differently.
If you are not sure which iOS version you have, go to Settings > General > About and look for "Software Version". If it says 16.1 or lower, use the older path. The information is the same either way — only the menu location changed.
What to do if your battery health is dropping fast
If your Maximum Capacity dropped more than 10% in the first six months, or more than 20% in the first year, something unusual is happening. This could mean a defective battery, or it could mean you are charging in a way that wears the battery faster than normal.
First, check your charging habits. Leaving your phone plugged in overnight every night, charging in hot environments, or using a damaged charger can all speed up battery wear. If you switch to charging during the day and unplugging when full, you may see the decline slow down.
If the decline continues or your phone is still under warranty, contact Apple. Bring your phone and the screenshot of your battery health report. Apple will run a diagnostic test and replace the battery for free if it is defective. If your phone is out of warranty, Apple will replace the battery for a fee, usually $50 to $100.
Why your battery health matters less than you think
Many people worry about battery health too much. A phone at 75% capacity is still perfectly usable — it just needs to be charged more often. If you charge every night anyway, you may never notice the difference. Battery health only becomes a real problem when it drops below 50%, and that usually takes four to five years of normal use.
The real reason to check battery health is to plan ahead. If you see 70% capacity and you plan to keep your phone for two more years, you might want to replace the battery now rather than wait for it to drop to 50%. If you plan to upgrade your phone in the next year, there is no reason to replace the battery at all.
How to take a screenshot of your battery health for your records
If you ever need to show Apple your battery health — for warranty service, for a trade-in, or just to have proof — take a screenshot. Open Settings > Battery > Battery Health & Charging, then press the Side Button and Volume Up at the same time (on older iPhones with a Home button, press Home and the Top button instead). The screenshot saves to your Photos app automatically.
You can also use the built-in Feedback Assistant to send Apple a report of your battery health. Open Settings > General > About, scroll down and tap Regulatory Info, then Battery Information. This shows more technical details that Apple uses for diagnostics.
Frequently Asked Questions
Is 80% battery health bad?
No. Apple designs batteries to reach 80% capacity after 1,000 charge cycles, which is about three years of daily charging. If you see 80% after two years, your battery is aging normally. You only need to worry when capacity drops below 50%.
Can I improve my battery health?
You cannot restore capacity that is already lost, but you can slow future wear. Charge during the day and unplug when full instead of leaving your phone plugged in overnight. Keep your phone cool — avoid using it in direct sunlight or in hot cars. Use an Apple charger or a certified third-party charger, not a damaged or counterfeit one.
What does it mean if Peak Performance Capability says my phone has experienced an unexpected shutdown?
Your battery got too weak to deliver power quickly, so iOS slowed down your processor to prevent sudden shutdowns. Your phone will feel slower, but it will not shut down unexpectedly. You can replace the battery to restore full speed, or accept the slower performance.
Should I replace my battery at 80% or wait until it is lower?
If your phone is under warranty or covered by AppleCare+, wait until the battery drops below 50% or you see Peak Performance messages. If you are out of warranty and paying out of pocket, replacing at 70% to 75% is reasonable if you plan to keep the phone for two more years. If you plan to upgrade soon, do not bother.
Why does my battery health show different percentages at different times?
Battery health can fluctuate by 1% to 2% depending on temperature and how recently you charged. This is normal. If it drops 5% or more between checks a few days apart, your phone may have a problem — contact Apple.