Replace your iPhone battery when it no longer holds a full charge through a normal day, when the phone shuts down unexpectedly at 20 percent or higher, or when the battery health drops below 80 percent

Your iPhone battery degrades with every charge cycle—this is normal chemistry, not a defect. After roughly 500 full charge cycles, most iPhone batteries retain about 80 percent of their original capacity. You will notice this as shorter time between charges, slower performance when the battery is low, or sudden shutdowns that seem to happen too early. Apple's Battery Health feature, built into every iPhone, tells you the exact percentage of capacity remaining. When that number drops below 80 percent and you are noticing real changes in how long your phone lasts, replacement becomes practical rather than optional.

The timing depends on your own use. If you charge your phone once a day and it still lasts through your day, there is no rush. If you are charging twice a day, carrying a power bank, or watching your phone shut itself down in the afternoon, replacement will give you back usable time. Battery replacement costs between $69 and $99 depending on your model, and takes about an hour at an Apple Store or authorized repair shop.

Key Takeaways

  • Check your battery health percentage in Settings > Battery > Battery Health & Charging to see the actual capacity remaining.
  • Replace the battery when health drops below 80 percent and you notice the phone dying faster or shutting down unexpectedly.
  • Sudden shutdowns at 20 percent battery or higher are a sign the battery cannot deliver the power your phone needs, even if the percentage seems high.
  • Battery replacement at an Apple Store or authorized repair shop costs $69 to $99 and takes about one hour.
  • Replacing the battery is usually cheaper and faster than replacing the entire phone if the rest of your device works well.

How to Check Your Battery Health Right Now

Open Settings, tap Battery, then tap Battery Health & Charging. You will see a percentage labeled "Maximum Capacity"—this is the amount of charge your battery can hold compared to when it was new. You will also see a "Condition" line that says either "Normal" or "Service Recommended." If it says "Service Recommended," Apple is telling you the battery is degraded enough that replacement makes sense.

Below that, you may see a line about "Peak Performance Capability." If your phone has been shutting down unexpectedly, this line will say something like "This iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power." This is the phone telling you the battery is failing, not just aging. This situation warrants replacement soon.

Signs Your Battery Needs Replacement Before It Fails Completely

The most obvious sign is that your phone dies faster than it used to. If you used to get a full day on one charge and now you are at 20 percent by mid-afternoon, the battery is losing capacity. This happens gradually, so you might not notice day to day, but comparing this week to last month will show the change.

Unexpected shutdowns are a second sign. Your phone shows 30 percent battery, then suddenly powers off. When you turn it back on, it boots normally and the percentage is still 30 percent. This happens because the battery cannot deliver the current your phone needs at that moment, even though it has charge stored. Cold weather makes this worse—a battery that shuts down at 30 percent indoors might shut down at 50 percent outside in winter.

Slower performance when the battery is low is a third sign. Your phone might lag, apps might close, or the camera might not work when the battery is below 20 percent. This is Apple's power management kicking in to prevent shutdowns, but it means the battery is struggling. If this is happening regularly, replacement will restore normal speed.

What Happens If You Wait Too Long

If you ignore a failing battery, the phone will eventually shut down and not turn back on until you charge it. This is not dangerous—it is the battery protecting itself—but it makes the phone unusable. You might be stuck without a phone in the middle of your day.

A severely degraded battery can also swell inside the phone, which can damage the screen or other components. This is rare but possible. If your phone feels thicker than it used to, or if the screen is lifting slightly at the edges, stop using it and take it to a repair shop when ready. Swelling is a sign to replace the battery or the phone right away, not to wait.

Where to Get Your Battery Replaced

Apple Stores offer battery replacement for the prices listed above. You can make an appointment through the Apple Support app or on apple.com. Bring your phone and a form of ID. The repair usually takes about an hour, though it can be longer if the store is busy. Your data stays on the phone—they do not erase it.

Apple Authorized Service Providers (independent repair shops certified by Apple) offer the same service at the same price. You can find one near you on apple.com by searching for "service providers." Some carriers like Verizon and AT&T also offer battery replacement, sometimes at the same price or slightly different depending on your plan.

If your phone is still under warranty or you have AppleCare+, battery replacement is covered at no cost as long as the battery health is below 80 percent. Check your coverage in the Apple Support app before you go in.

The Difference Between Battery Replacement and Phone Replacement

Battery replacement costs $69 to $99 and takes an hour. Phone replacement costs $300 to $1,200 depending on the model and whether you buy new or refurbished. If your phone is otherwise working well—the screen is not cracked, the camera works, it is not slow—battery replacement is almost always the better choice. You get a phone that feels new again for a fraction of the cost of a new device.

The only time phone replacement makes more sense is if your phone has other damage that would cost more to fix than the phone is worth, or if the phone is old enough that repairs are becoming hard to find. If your battery is the only problem, replace the battery.

How to Make Your Battery Last Longer Between Replacements

Charge your phone to 80 percent instead of 100 percent when you can. iPhones have a feature called Optimized Battery Charging that learns your charging habits and stops charging at 80 percent overnight, then finishes the last 20 percent an hour before you usually wake up. This reduces the stress on the battery. Turn it on in Settings > Battery > Battery Health & Charging.

Keep your phone cool. Heat degrades batteries faster than anything else. Do not leave your phone in a hot car, in direct sun, or in a pocket against your body for hours. If your phone feels warm to the touch while charging, unplug it and let it cool down.

Use a lower screen brightness when you can, and turn on Low Power Mode when the battery drops to 20 percent. These steps reduce the current your battery has to deliver, which slows degradation. They also help you get through the day on a single charge, which means fewer charge cycles per week.

Frequently Asked Questions

Can I replace my iPhone battery myself?

You can, but it is not recommended unless you have experience with phone repair. The battery is glued in, and removing it without damaging the screen or other components requires special tools and care. If you damage something during the repair, you will end up paying more than the original battery replacement would have cost. Professional replacement is safer and faster.

Will replacing the battery erase my data?

No. Apple and authorized repair shops do not erase your phone during battery replacement. Your photos, messages, apps, and settings all stay exactly as they are. The phone is opened, the old battery is removed, a new one is installed, and it is closed back up.

How long does a new battery last?

A new battery will retain about 80 percent capacity after roughly 500 charge cycles, which is typically two to three years of normal daily use. After that, you will notice the same gradual decline you saw with the old battery. The timeline depends on how often you charge and how you use your phone.

What if my phone is out of warranty?

You still pay the standard battery replacement fee of $69 to $99. Warranty does not matter for battery replacement—Apple charges the same price whether your phone is one year old or five years old. The only exception is if you have AppleCare+, which covers battery replacement at no cost.

Is it worth replacing the battery in an old iPhone?

If the phone is otherwise working well and you want to keep using it, yes. A $79 battery replacement can give you another year or two of usable life. If the phone is so old that parts are hard to find, or if other components are failing, it might be time to replace the phone instead. But for most people, battery replacement extends the life of a working phone cheaply.