Replace your iPhone battery when it no longer holds a charge through a full day, shuts down unexpectedly at 20–30% battery, or shows a red battery icon constantly

Your iPhone battery degrades over time. Every charge cycle — from full to empty and back — wears it down a little. After roughly 500 full charge cycles, most iPhone batteries retain only 80% of their original capacity. After 1,000 cycles, they typically hold 60% or less. You do not have to wait until the battery is completely dead to replace it. The right time is when the battery's behaviour starts affecting how you use your phone.

Apple considers a battery "worn out" when it can no longer hold 80% of its original capacity. At that point, a replacement makes sense. But you may want to replace it sooner if the phone is shutting down unexpectedly, draining faster than it used to, or requiring a charge multiple times a day when it did not before.

Key Takeaways

  • Check your battery health in Settings > Battery > Battery Health & Charging to see the current capacity percentage.
  • Replace the battery if capacity has dropped below 80% or if the phone shuts down unexpectedly at 20–30% charge.
  • Unexpected shutdowns happen when the battery cannot deliver the power the phone needs, even though it shows charge remaining.
  • Apple and authorized repair shops can replace the battery; third-party repairs are cheaper but may void your warranty.
  • Battery replacement typically costs $69–$99 at Apple, depending on your iPhone model and whether it is under warranty.

How to check your battery health right now

Open Settings on your iPhone. Tap Battery, then Battery Health & Charging. You will see a percentage labeled "Maximum Capacity." This number tells you how much charge your battery can hold compared to when it was new. If it shows 85%, your battery holds 85% of its original charge capacity.

Below that, you may see a message about battery condition. If it says "Normal," your battery is working as expected. If it says "Service Recommended," the battery has degraded enough that Apple suggests replacing it. If it says "Service Battery," the battery needs replacement soon.

Write down the percentage. Check it again in a few months. If it drops 5–10% every few months, you are on a normal degradation curve. If it drops 20% in a month, the battery is failing faster than usual.

Unexpected shutdowns are a sign to replace the battery sooner

Some iPhones shut down suddenly even when the battery shows 20%, 30%, or higher charge. This happens because the battery cannot deliver the power the phone needs in that moment — usually during a demanding task like taking a photo, making a call, or opening an app. The phone protects itself by shutting down rather than damaging the battery.

If your phone shuts down once or twice a month, it is annoying but not urgent. If it shuts down multiple times a week or every day, the battery needs replacement. You can test this by letting the phone sit for 30 minutes, then turning it back on. If it turns on and shows the same battery percentage it showed before the shutdown, the battery is the problem.

Unexpected shutdowns do not always mean the battery is at 80% capacity or lower. A battery at 85% capacity can still cause shutdowns if it is damaged or defective. The capacity percentage and the shutdown behaviour are separate signals.

What happens if you wait too long to replace the battery

If you ignore the "Service Battery" message and keep using the phone, the shutdowns will become more frequent. Eventually the phone may shut down so often that it becomes unusable — you cannot complete a call, send a message, or take a photo without it powering off.

A degraded battery does not damage other parts of your phone. It will not cause the screen to fail, the camera to break, or the logic board to stop working. But it will make the phone frustrating to carry and use. If you rely on your phone for work or emergencies, waiting until the battery is completely unreliable is a risk.

Where to get the battery replaced

Apple Stores and Apple Authorized Service Providers can replace your battery. You can also mail your phone to Apple if there is no store near you. The process usually takes one to three business days at a store, longer by mail.

Third-party repair shops — including many local phone repair businesses — can also replace iPhone batteries, often for $40–$60 less than Apple charges. The trade-off is that third-party repairs may void your warranty or AppleCare+ coverage, and the quality of the replacement battery can vary. Some third-party shops use genuine Apple batteries; others use aftermarket batteries that may not last as long.

Before choosing a repair shop, ask whether they use genuine Apple batteries or aftermarket ones, and whether the repair affects your warranty. If your phone is still under warranty or you have AppleCare+, Apple or an authorized provider is usually the safer choice.

Battery replacement cost and what is covered

Apple charges $69 for iPhone 15 and newer models, $79 for iPhone 14 and earlier models, and $99 for iPhone X and older. These prices vary slightly by region. If your phone is within the one-year limited warranty and the battery failure is a manufacturing defect (not normal wear), Apple replaces it at no cost. If you have AppleCare+, battery replacement is covered at no cost as long as the coverage is active.

Outside of warranty or AppleCare+, you pay the full replacement cost. Some people choose to replace the battery themselves using a kit from a third-party seller, but this requires opening the phone and risks damaging the screen, logic board, or water sealing. Unless you have experience with phone repair, professional replacement is worth the cost.

How long a new battery lasts

A replacement battery from Apple or an authorized provider will last roughly 500 full charge cycles before it drops to 80% capacity again. That is typically two to three years of normal use. If you charge your phone once a day, you will get closer to three years. If you charge it twice a day, you will reach 500 cycles sooner.

You can extend battery life by keeping your phone cool, avoiding extreme heat, and not letting it drain completely very often. Charging to 80% and stopping there, rather than charging to 100%, also slows degradation — though most people find this impractical for daily use.

Frequently Asked Questions

Can I replace the battery myself?

You can buy a replacement battery kit online and follow a guide, but it requires opening your phone with specialized tools and risks damaging the screen, water sealing, or internal components. Most people should have a professional do it. If you do attempt it yourself, you will void your warranty.

Will replacing the battery make my phone feel new again?

A new battery will restore the phone's ability to hold a full day of charge and eliminate unexpected shutdowns. It will not make the phone faster, improve the camera, or update the software. If the phone feels slow for other reasons, a battery replacement alone will not fix that.

What if my battery capacity is at 85% but the phone works fine?

You do not have to replace it when ready. If the phone lasts a full day on a single charge and does not shut down unexpectedly, you can wait. Check the capacity again in three to six months. Replace it when the capacity drops below 80% or when the phone's behaviour becomes inconvenient.

Does cold weather affect when I should replace the battery?

Cold temporarily reduces battery performance — your phone may show lower charge or shut down in freezing temperatures even if the battery is healthy. Warm it up indoors and the battery will work normally again. This is not a sign the battery needs replacement. Actual battery degradation is permanent and shows up in the Battery Health percentage.

Can I use my phone while it is being repaired?

No. The repair takes one to three business days at minimum, and your phone will be in the shop the whole time. If you cannot be without your phone, ask the shop whether they have a loaner device, or plan the repair for a time when you have a backup phone available.