Where to find your iPhone battery health information
Your iPhone stores battery health data in the Settings app under Battery, where you can see the current capacity of your battery compared to when it was new. Open Settings, tap Battery, then tap Battery Health & Charging. The screen shows two numbers: Maximum Capacity (what percentage of the original charge your battery can now hold) and Peak Performance Capability (whether your phone is running at full speed or if iOS has slowed it down to protect the battery).
This information is built into every iPhone running iOS 11.3 or later. You do not need to read anything or use a third-party tool — Apple includes this data as a standard feature. The numbers update as your battery ages, so you can check back periodically to watch the trend.
Key Takeaways
- Maximum Capacity shows what percentage of the original battery charge your phone can now hold, and anything above 80 percent is considered healthy for daily use.
- Peak Performance Capability tells you whether iOS has slowed down your phone to protect an aging battery, which happens automatically when capacity drops significantly.
- You can check this information anytime by going to Settings > Battery > Battery Health & Charging, and the data updates as your battery ages.
- If your battery capacity falls below 80 percent and you want to restore full performance, Apple offers battery replacement at a cost that varies by iPhone model.
What Maximum Capacity means and when to worry
Maximum Capacity is a percentage that tells you how much charge your battery can hold right now compared to when it left the factory. A new iPhone battery is at 100 percent. After a year or two of normal use, it might drop to 90 or 95 percent. After three or four years, it might be at 80 percent or lower.
Apple considers a battery healthy if it retains at least 80 percent of its original capacity. Below 80 percent, the battery is aging faster than normal, and you may notice that your phone does not last as long between charges. This does not mean the battery is broken — it means the battery is wearing out the way all rechargeable batteries do over time.
If your capacity is still above 80 percent, your battery is performing normally for its age. You do not need to replace it unless you want longer battery life. If it has dropped below 80 percent and you are frustrated with how quickly your phone drains, battery replacement is the solution.
Understanding Peak Performance Capability
Peak Performance Capability tells you whether your iPhone is running at full speed or whether iOS has automatically slowed it down. When a battery gets very old or damaged, it cannot deliver power as quickly as the phone needs it. Instead of crashing, iOS reduces the phone's speed so the battery can keep up. This is called throttling.
If Peak Performance Capability says "Your battery is in good condition" or "Your battery is in normal condition," your phone is running at full speed. If it says "Your battery's health is significantly degraded" or mentions that performance has been reduced, iOS has slowed your phone down to protect the battery.
You can turn off this slowdown in the same Battery Health & Charging screen, but doing so may cause your phone to shut down unexpectedly if the battery cannot deliver the power the phone is trying to use. Most people leave it on. If the slowdown bothers you, battery replacement will restore full speed.
How battery capacity changes over time
Every rechargeable battery loses capacity gradually. The rate depends on how you use your phone, how often you charge it, and the temperature where you keep it. Leaving your phone in a hot car or in direct sunlight speeds up battery aging. Keeping it cool and charging it regularly (rather than letting it drain completely) slows aging.
A typical iPhone battery loses about 1 percent of capacity per month with normal use. After one year, you might see 85 to 95 percent capacity. After two years, 75 to 85 percent. After three years, 65 to 75 percent. These are rough ranges — your phone may age faster or slower depending on your habits.
If your capacity is dropping much faster than this (losing 10 or 20 percent in just a few months), your battery may be defective. Contact Apple Support to discuss whether your battery qualifies for replacement under warranty or at a reduced cost.
When to replace your iPhone battery
You should consider battery replacement when Maximum Capacity drops below 80 percent and you notice your phone does not last through a full day of normal use. Replacement is also worth considering if iOS has throttled your phone's performance and you want full speed back without buying a new phone.
Apple offers battery replacement at Apple Stores and through Apple's mail-in repair service. The cost varies by iPhone model — typically between $50 and $70 for recent models. If your phone is still under warranty or covered by AppleCare+, the replacement may be free or discounted. If your battery is defective (capacity dropped very quickly), Apple may replace it at no cost even outside warranty.
Third-party repair shops also offer battery replacement, often at a lower price than Apple. The trade-off is that third-party repairs may not include the same warranty, and some shops may not use genuine Apple batteries. If you choose a third-party shop, ask whether they use original or aftermarket batteries and what warranty they offer.
Other battery information in Settings
The Battery Health & Charging screen also shows Charging Optimization, a feature that learns when you usually charge your phone and slows charging to 80 percent until you need the phone. This reduces the time the battery spends at 100 percent, which slows aging. You can turn this on or off depending on your preference.
If you want to see which apps are draining your battery right now, go to Settings > Battery and look at Battery Usage. This shows which apps have used the most power in the last 24 hours or the last 10 days. Apps that use a lot of power in the background (like location services or constant notifications) will show up here.
Battery Usage is different from Battery Health. Battery Usage tells you what is draining your battery today. Battery Health tells you how much capacity your battery has left. Both are useful for different reasons — Battery Health helps you decide whether to replace the battery, and Battery Usage helps you decide which apps to close or adjust.
Frequently Asked Questions
What is a normal battery capacity for an iPhone that is one year old?
A one-year-old iPhone typically has a battery capacity between 85 and 95 percent, depending on how much you have charged it and the temperatures it has been exposed to. If your one-year-old phone is already below 80 percent, the battery may be aging faster than normal, and you can contact Apple to discuss whether it qualifies for replacement.
Does checking battery health drain the battery?
No. Opening Settings and looking at Battery Health & Charging uses almost no power. You can check it as often as you want without affecting your battery.
Can I improve my battery capacity by changing settings?
No. Battery capacity is a physical property of the battery itself and cannot be improved by changing settings. You can slow down how fast capacity decreases by keeping your phone cool, avoiding extreme temperatures, and using Charging Optimization, but you cannot restore capacity that has already been lost. Battery replacement is the only way to restore full capacity.
Why does my battery capacity say 100 percent but my phone still dies quickly?
If your battery shows 100 percent capacity but your phone drains fast, the issue is probably not the battery itself. Check Battery Usage in Settings to see which apps are draining power. You may also have background app refresh turned on for apps you do not use, or location services may be running constantly. Closing unused apps and turning off background refresh can help.
Is it safe to use my iPhone if the battery capacity is below 50 percent?
Yes, it is safe. A battery at 50 percent capacity is old and will not last long between charges, but it will not damage your phone or cause a safety problem. If iOS has throttled your performance because the battery is very old, your phone may feel slow, but it will not be harmed by using it.