Where to find your iPhone battery information
Your iPhone stores battery health data in Settings, under a section called Battery. Open Settings, scroll down to Battery, then tap Battery Health & Charging. You will see two numbers: your current maximum capacity (shown as a percentage) and the peak performance capability.
Maximum capacity tells you how much charge your battery holds now compared to when it was new. A new iPhone shows 100%. After normal use over months or years, this number drops — a battery at 80% holds four-fifths of the charge it once did. Peak performance capability tells you whether your iPhone is running at full speed or whether the system has slowed the processor to protect an aging battery.
This same Settings menu also shows you which apps have used the most battery power in the last 24 hours or the last 10 days. Tap the clock icon next to "Battery Health & Charging" to switch between these two views.
Key Takeaways
- Maximum capacity percentage in Settings > Battery > Battery Health & Charging shows how much charge your battery holds compared to when it was new.
- Peak performance capability tells you whether your iPhone is running at full processor speed or has been slowed to protect the battery.
- The Battery menu also lists which apps consumed the most power in the last 24 hours or 10 days, helping you spot power drains.
- A battery below 80% maximum capacity may drain faster during the day, but this is normal wear and does not mean the battery is defective.
Understanding maximum capacity and what the percentage means
Maximum capacity is measured against the battery's original design capacity. When you first buy an iPhone, the battery is at or near 100% of its design capacity. Over time, the chemical compounds inside the battery degrade with every charge cycle. A charge cycle is one full discharge from 100% to 0%, though partial charges count toward a cycle too.
A battery at 80% maximum capacity still works — it straightforward holds less energy. If your iPhone used to last a full day at 100%, it may last 16 hours at 80%. The phone itself does not break; it just needs charging more often. Apple considers 80% the threshold where a battery may be worth replacing if you want the original all-day runtime back, but the battery is not defective at 79%.
Maximum capacity naturally declines faster if you regularly charge your iPhone in hot environments, leave it plugged in overnight constantly, or drain it completely and recharge it repeatedly. Moderate use in normal temperatures slows this decline.
What peak performance capability means
Peak performance capability has two possible states: either your iPhone is running at full speed, or it has activated a feature called dynamic power management. When dynamic power management is on, your iPhone slows the processor slightly to reduce the power draw on an aging battery. This prevents unexpected shutdowns when the battery cannot deliver the power the processor demands.
If you see a message saying "Peak Performance Capability: Reduced," your battery is aging enough that the system has decided to protect it by limiting speed. This is not a malfunction — it is a safety measure. You will notice apps open slightly slower and scrolling may feel less smooth, but the phone remains usable. If you want full speed back, you can replace the battery.
If the message says "Peak Performance Capability: Normal," your battery is either new or still healthy enough that the system does not need to slow down. This does not mean the battery will never degrade; it means it has not degraded enough yet to trigger the slowdown.
Reading the battery usage breakdown by app
Below the maximum capacity and peak performance information, you will see a list of apps ranked by how much battery they used. The percentage next to each app shows what share of total battery drain that app caused. An app using 25% means it consumed one-quarter of your battery power since the last full charge.
Tap the clock icon to switch between "Last 24 Hours" and "Last 10 Days." The 24-hour view shows recent heavy use — if you streamed video for two hours today, the video app will rank high. The 10-day view shows which apps drain power consistently over time. An app that uses 5% every single day is a bigger concern than one that used 20% once.
Some apps, like Maps or video streaming, naturally use more battery because they run the screen at full brightness and use the processor heavily. Others, like email or messaging, should use very little. If an unexpected app is using 15% or more, check whether it is running in the background or has a setting you can adjust.
Checking battery usage in Low Power Mode
Low Power Mode reduces battery drain by limiting background activity, dimming the screen, and slowing performance. You can turn it on manually in Settings > Battery, or your iPhone can turn it on automatically when the battery drops to 20% (or 10%, depending on your model).
When Low Power Mode is active, the battery percentage in the top right corner of your screen turns yellow. The Battery menu will show "Low Power Mode: On." While Low Power Mode is active, the battery usage percentages you see still reflect real drain, but the overall drain rate will be slower because fewer processes are running.
Low Power Mode does not damage the battery or change its maximum capacity. It is a temporary setting you can turn off anytime. Many people turn it on when they know they will not have access to a charger for several hours.
Why your battery percentage drops faster over time
As maximum capacity declines, your battery percentage drops faster during the day because the battery holds less total energy. A battery at 50% maximum capacity has half the energy of a new battery, so it drains to 0% in roughly half the time. This is not a sign of a problem — it is the expected result of battery aging.
If your battery drains much faster than the maximum capacity percentage would predict, the cause is usually an app using power in the background, the screen brightness set too high, or location services running constantly. Check the battery usage list to see which apps are consuming the most power, and consider disabling background activity for apps you do not need to update constantly.
Extreme heat also causes faster drain. If your iPhone feels warm to the touch, move it to a cooler location and avoid using it while charging. Heat speeds up chemical degradation inside the battery, so keeping your iPhone cool extends its lifespan.
When to consider replacing your battery
Apple and most repair shops offer battery replacement when maximum capacity drops below 80%. You do not have to wait until then — if your iPhone drains too quickly for your needs, you can replace the battery at any point. The cost varies by model, but Apple's official service typically ranges from $50 to $70.
If your iPhone is still under warranty or covered by AppleCare+, battery replacement may be covered if the maximum capacity has dropped below 80% due to normal use. Check your coverage status in Settings > General > About, then tap Service & Support.
Third-party repair shops often charge less than Apple, but quality varies. If you choose a third-party repair, confirm they use new batteries (not refurbished) and offer a warranty on the replacement.
Frequently Asked Questions
Is it bad if my maximum capacity is below 80%?
No. Below 80% is normal wear after a year or more of use. The battery still works; it straightforward holds less charge. You will need to charge more often, but the phone is not damaged. Battery replacement is optional and depends on whether the reduced runtime fits your needs.
Can I improve my battery health or bring the percentage back up?
No. Maximum capacity only declines; it does not recover. Once the chemical compounds inside the battery degrade, they cannot be restored. You can slow future decline by avoiding heat, not leaving the phone plugged in overnight constantly, and not draining it completely, but you cannot reverse past decline.
Why does my battery drain faster in cold weather?
Cold slows the chemical reactions inside the battery, so it temporarily cannot deliver power as quickly. Your iPhone may shut down at 20% battery in freezing weather, even though the battery is not damaged. The battery recovers normal performance when it warms up. Extreme cold can cause permanent damage, so avoid leaving your iPhone outside in freezing temperatures for long periods.
What does "service recommended" mean in the battery menu?
This message appears when the battery has degraded significantly or when the system detects a hardware problem. It does not mean your phone will stop working when ready, but it means the battery should be checked or replaced soon. Contact Apple or an authorized repair shop to have the battery tested.
Does using Low Power Mode all the time damage my battery?
No. Low Power Mode straightforward limits background activity and reduces performance temporarily. It does not affect the battery's maximum capacity or lifespan. You can use it as much as you want without harming the battery.