Every iPhone has a built-in rechargeable battery
Yes, every iPhone model comes with a lithium-ion rechargeable battery sealed inside the device. You cannot remove it yourself—Apple stopped making user-replaceable batteries in iPhones years ago. The battery powers everything: the screen, the processor, the camera, the cellular radio. When it wears out, you have to replace the entire battery through Apple, an authorized repair shop, or a third-party repair service.
The battery capacity varies by model. An iPhone 15 Pro Max holds more charge than an iPhone 15, which holds more than an iPhone SE. Larger phones generally have larger batteries because they have more physical space. The capacity is measured in milliamp-hours (mAh), though Apple usually just publishes how many hours of video playback or talk time you can expect.
Key Takeaways
- iPhones use non-removable lithium-ion batteries that are sealed inside the phone and cannot be swapped out by the user.
- Battery capacity decreases over time—after about 500 full charge cycles, most iPhone batteries retain roughly 80 percent of their original capacity.
- You can check your battery health in Settings > Battery > Battery Health & Charging to see the current maximum capacity percentage.
- Apple and authorized repair shops can replace your battery, though third-party repair is cheaper and often faster.
- Newer iPhones support faster charging speeds and wireless charging, but the battery itself still degrades with normal use.
How iPhone batteries degrade over time
Lithium-ion batteries lose capacity every time you charge them. This is normal chemistry, not a defect. After roughly 500 full charge cycles (a cycle is draining the battery completely and charging it back to 100 percent), most iPhone batteries drop to about 80 percent of their original capacity. After 1,000 cycles, they typically sit around 60 to 70 percent.
A charge cycle does not mean one day of use. If you charge your phone from 20 percent to 100 percent, that is one cycle. If you charge it from 50 percent to 100 percent, that is half a cycle. Most people complete one to two cycles per day depending on usage.
The speed of degradation also depends on temperature and charging habits. Keeping your phone hot while charging, or letting it sit at 100 percent for hours, speeds up wear. Charging to 80 percent and stopping there slows degradation, which is why newer iPhones include an "Optimized Battery Charging" feature that learns your charging routine and holds the charge at 80 percent until you need it.
How to check your battery health
You can see exactly how much capacity your battery has lost without opening the phone. Go to Settings, then Battery, then Battery Health & Charging. The screen shows "Maximum Capacity" as a percentage. If it says 85 percent, your battery is at 85 percent of what it was new.
The same screen also shows "Condition" — either "Normal" or "Service Recommended." Apple marks a battery as needing service when capacity drops below 80 percent, though the phone will still work. You do not have to replace it when ready; many people run phones at 70 or 60 percent capacity for months or years before replacing the battery.
Battery replacement options and costs
Apple replaces batteries at its stores and through mail-in service. The cost is usually between $50 and $70 depending on the model, though if your phone is still under warranty or covered by AppleCare+, the replacement may be free. Turnaround is typically one to three days in-store, or about a week by mail.
Authorized Apple repair shops (Best Buy's Genius Bar, carrier stores, and independent shops with Apple certification) charge the same price and offer similar timelines. They are legitimate and use genuine Apple parts.
Third-party repair shops charge $30 to $50 and often complete the work same-day or next-day. They may use aftermarket batteries that are not made by Apple but are often reliable. The trade-off is that you lose any remaining warranty coverage on the phone, and if something goes wrong during the repair, the shop may not be liable. Check reviews before choosing a third-party shop.
What affects how fast your battery drains
Battery drain speed depends on what you are doing. Streaming video, gaming, or using GPS drains the battery much faster than reading text or checking email. The screen brightness also matters—a bright screen uses far more power than a dim one. Background app refresh, location services, and Bluetooth all consume power even when you are not actively using the phone.
If your battery drains unusually fast even though the health percentage is still high (above 80 percent), a misbehaving app or setting may be the culprit, not the battery itself. Check Settings > Battery to see which apps have used the most power in the last 24 hours or 10 days. If one app is using far more than others, try closing it or uninstalling it.
Charging speed and wireless charging
Newer iPhones support faster wired charging than older models. An iPhone 15 can charge at up to 20 watts with a compatible charger, while an iPhone 14 maxes out at 18 watts. Older models charge slower. Wireless charging is available on most iPhones from the iPhone 8 onward, but it is slower than wired charging—typically 5 to 7.5 watts depending on the charger.
Faster charging does not damage the battery if you use an Apple-certified charger or a reputable third-party charger. The phone manages the charging speed automatically to protect the battery. Using a very cheap or damaged charger can cause problems, but a quality charger will not harm the battery faster than normal use would.
When to replace your iPhone battery
Replace the battery when the phone no longer lasts through your day, or when the maximum capacity drops below 70 percent and you want better performance. There is no hard important date—a phone at 60 percent capacity still works, it just needs charging more often.
If your phone is more than three or four years old and the battery is below 80 percent, replacing the battery is usually cheaper than buying a new phone and extends the life of your device by another year or two. If the phone is very old or has other problems (cracked screen, broken buttons, water damage), a new phone may be the better choice.
Frequently Asked Questions
Can I replace my iPhone battery myself?
Not easily. iPhones are sealed with adhesive, and opening one requires special tools and skill. Attempting it risks damaging the screen, logic board, or other components. Unless you have experience with phone repair, use Apple, an authorized shop, or a trusted third-party repair service.
Does using my phone while charging damage the battery?
No, it does not damage the battery itself, but it does generate heat, which speeds up degradation slightly. If you regularly use your phone while charging, the battery may wear out a bit faster than if you let it charge uninterrupted. The difference is small over a year or two.
Why does my iPhone battery drain so fast after an update?
After a major iOS update, the phone indexes files and processes data in the background for a day or two, which uses extra power. This is temporary. If fast drain continues after a few days, check which apps are using the most battery in Settings > Battery, or restart the phone.
Is it bad to leave my iPhone charging overnight?
Modern iPhones have "Optimized Battery Charging" that stops charging at 80 percent until you need the phone, so overnight charging does not significantly harm the battery. However, if you charge to 100 percent and leave it plugged in for many hours, the battery sits at full capacity longer, which does speed up wear slightly.
What is the difference between battery capacity and battery health?
Capacity is the total amount of charge the battery can hold, measured in mAh. Health is the percentage of original capacity remaining—a 3,000 mAh battery at 80 percent health holds 2,400 mAh. Health is what you see in Settings; capacity is a technical spec you find in Apple's documentation.