Where to Find Battery Health on Your iPhone
Your iPhone stores battery health information in Settings, and you can view it in under a minute. Open Settings, then tap Battery, then Battery Health & Charging. You will see a percentage labeled Maximum Capacity — this is your battery's current health.
Maximum Capacity shows how much charge your battery can hold compared to when it was new. A new iPhone shows 100%. As you use the phone, this number gradually drops. At 80% capacity, your battery is still functioning normally, though it will not last as long per charge as it did originally. Apple considers a battery degraded when it falls below 80%.
Below Maximum Capacity, you may also see Peak Performance Capability. This line tells you whether your phone is running at full speed or whether iOS has slowed the processor to protect an aging battery. If it says "Your battery is in good condition," your phone runs at full speed. If it mentions performance management, your battery is significantly worn and the system has reduced power to prevent unexpected shutdowns.
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 or higher is considered healthy; below 80% means the battery is degrading faster than normal.
- Peak Performance Capability tells you whether iOS has slowed your phone's processor to protect the battery from shutting down unexpectedly.
- Battery health declines naturally over time with normal use, and the rate depends on how often you charge, the temperatures you expose the phone to, and which iOS version you run.
- You can see which apps and features are using the most power in Battery Usage, located in the same Battery settings menu.
What Maximum Capacity Actually Means
Maximum Capacity is not the same as your current battery percentage. Your current percentage appears at the top of the screen or in Control Center — it tells you how much charge is in the battery right now. Maximum Capacity tells you the upper limit of what that battery can hold.
Think of it like a gas tank. If your car's tank originally held 15 gallons but now holds only 12 gallons because the tank has corroded, 12 gallons is your "maximum capacity." You can still fill it completely, but the total amount is less. Your iPhone's battery works the same way. At 80% capacity, a full charge gives you 80% of the runtime you got when the phone was new.
Capacity drops because lithium-ion batteries — the type in all iPhones — lose the ability to hold charge over time. This is a chemical process that happens whether you use the phone or not, though usage patterns, temperature, and charging habits speed it up. You cannot stop this decline, but you can slow it by avoiding extreme heat, not letting the battery drain completely, and not charging to 100% every single day.
How to See Which Apps Are Draining Your Battery
Below Battery Health & Charging, in the same Settings > Battery menu, you will find Battery Usage. Tap it to see a list of apps ranked by how much power they have used in the last 24 hours or the last 10 days — switch between the two with the toggle at the top.
The percentage next to each app shows what share of your total battery that app consumed. If Safari shows 35%, it used 35% of the power your phone drew in that time period. This does not mean the app is broken; heavy use of any app will show a high percentage. Maps, video streaming, and games naturally use more power than text messaging.
If an app shows a high percentage but you barely used it, that is a sign the app may be running in the background more than expected. Close the app completely and check again in a few hours. If the percentage stays high without you opening it, the app may have a bug or may be set to refresh in the background. You can turn off background refresh for individual apps in Settings > General > Background App Refresh.
Understanding Peak Performance Capability
Peak Performance Capability appears only if your battery has degraded significantly. When it shows "Your battery is in good condition," your iPhone is running at full processor speed. When it shows that performance management is active, iOS has automatically reduced your phone's speed to prevent the battery from shutting down unexpectedly.
This slowdown happens because a worn battery cannot deliver power as quickly as a new one. Under heavy load — like opening a large photo library or running a game — an old battery's voltage can drop suddenly, causing the phone to shut off even though the battery is not empty. Apple's solution is to reduce the processor speed so the battery never has to deliver that much power at once. The phone still works, but tasks take longer.
If performance management is on and you find the slowdown frustrating, you have one real option: replace the battery. Apple offers battery replacement at an Apple Store or authorized service provider. The cost varies by iPhone model but typically ranges from $50 to $100. After replacement, your Maximum Capacity will reset to 100% and performance management will turn off.
Why Your Battery Health Drops Faster Than Expected
Battery capacity declines at different rates depending on how you use and charge your phone. Heat is the biggest factor — lithium-ion batteries degrade much faster in hot conditions. If you regularly use your iPhone in direct sunlight, in a hot car, or while charging during heavy use, the battery will age faster. Keeping your phone cool, especially while charging, slows degradation.
Charging habits also matter. Charging to 100% every day and letting the battery drain to 0% regularly both speed up wear. If you want to slow degradation, charge to around 80% and avoid letting the battery drop below 20%. iOS 13 and later include Optimized Battery Charging, which you can turn on in Settings > Battery > Battery Health & Charging. This feature learns your charging patterns and holds the battery at 80% until shortly before you usually wake up, then charges the last 20% quickly. This reduces the time the battery spends at high charge levels, which slows aging.
The iOS version you run also affects battery health. Older iOS versions sometimes have bugs that cause excessive power drain. If your battery health is dropping unusually fast, check Settings > General > Software Update to make sure you are running the latest version for your iPhone model.
When to Replace Your Battery
You do not have to replace your battery the moment it drops below 80%. Many people use iPhones with 70% or 60% capacity without problems. Replace the battery when one of these things happens: your phone shuts down unexpectedly even though the battery percentage is not zero, performance management is slowing the phone noticeably, or the battery no longer lasts long enough for your daily use.
If your iPhone is still under warranty or covered by AppleCare+, battery replacement may be free if capacity has dropped below 80% due to a defect (not normal wear). If you are out of warranty, you will pay the service fee. You can start a repair through apple.com, at an Apple Store, or through an authorized service provider. The process usually takes a few days to a week.
Third-party repair shops also offer battery replacement, often for less money than Apple. If you choose this route, make sure the shop uses genuine or high-quality replacement batteries — cheap batteries may have lower capacity or degrade faster. Ask the shop what warranty they offer on the replacement battery.
Frequently Asked Questions
Is 85% battery health bad?
No. Apple considers 80% and above healthy. At 85%, your battery still holds most of its original charge capacity and will likely last several more years of normal use before you need to replace it. You may notice the phone does not last quite as long per charge as it did when new, but performance management will not be active.
Can I improve my battery health after it drops?
No. Battery capacity only declines; it cannot be restored through settings changes, updates, or usage patterns. Once a battery has lost capacity, the only way to restore it is to replace the battery itself. You can only slow future decline by keeping the phone cool, using Optimized Battery Charging, and avoiding extreme charge levels.
Why does my battery health say 100% but my phone dies quickly?
Maximum Capacity and actual runtime are different things. If your battery shows 100% capacity but drains fast, a single app or feature is probably using excessive power. Check Battery Usage to find the culprit, or restart your phone. If the problem persists after a restart, the battery itself may be defective even though capacity tests normal — contact Apple or an authorized service provider.
Does Optimized Battery Charging actually work?
Yes, but only if your charging pattern is consistent. The feature learns when you usually charge and wake up, then adjusts charging to keep the battery at 80% until shortly before you need it. If you charge at random times or travel frequently, the feature may not help much. It is still worth turning on because it cannot hurt and may slow degradation if your routine is regular.
What is the difference between battery health and battery percentage?
Battery percentage is how much charge is in your battery right now — the number you see in Control Center. Battery health (Maximum Capacity) is the upper limit of how much charge the battery can hold. A phone at 50% charge with 80% health has half its current battery drained but a healthy battery overall. A phone at 100% charge with 40% health is fully charged but the battery is significantly worn.