Signs your iPhone battery is failing

Your iPhone battery is ready to replace when it no longer holds a charge through a normal day, shuts down unexpectedly even when the battery percentage shows 20 percent or higher, or charges to 100 percent but drains within hours of light use. These are the three clearest signals that the battery itself has degraded, not that you need to change your habits.

A battery that worked fine for two years and suddenly fails is normal wear. Lithium batteries lose capacity over time — this is chemistry, not a defect. After roughly 500 full charge cycles (a full cycle means charging from 0 to 100 percent), most iPhone batteries retain about 80 percent of their original capacity. By 1,000 cycles, that drops to around 70 percent.

Do not confuse a failing battery with a phone that straightforward needs a restart or a settings adjustment. If your phone is new or less than a year old and drains quickly only when you run specific apps, the problem is usually software, not the battery itself. Restart the phone first. If the problem persists across multiple days and multiple apps, then the battery is likely the culprit.

Key Takeaways

  • Replace your iPhone battery when it no longer lasts a full day of normal use, shuts down unexpectedly at 20 percent charge or higher, or charges fully but drains within hours.
  • Most iPhone batteries degrade naturally after 500 to 1,000 charge cycles, which typically takes two to three years of regular use.
  • Apple's Battery Health feature in Settings shows your battery's current capacity as a percentage — below 80 percent usually means replacement is worth considering.
  • Authorized Apple service locations and some third-party repair shops can replace the battery, though Apple's warranty covers battery replacement only if capacity has dropped below 80 percent within one year.

How to check your battery health in Settings

Open Settings, then tap Battery, then Battery Health & Charging. You will see a percentage labeled "Maximum Capacity" — this is how much charge your battery can hold compared to when it was new. If it shows 80 percent or higher, your battery is still within normal range. If it shows below 80 percent, Apple considers it degraded.

You will also see a line labeled "Condition" that says either "Normal" or "Service Recommended." If it says "Service Recommended," Apple is telling you the battery should be replaced. This does not mean your phone will stop working today, but it means the battery has degraded enough that replacement will noticeably improve performance and battery life.

Write down the percentage you see. Check it again in two weeks. If the percentage dropped more than 5 percent in that time, the battery is failing rapidly and replacement should happen soon. If it stayed the same or dropped only 1 to 2 percent, the battery is degrading normally and you can plan replacement for whenever it becomes inconvenient enough to justify the cost and time.

When to replace before the battery completely fails

Replace your battery before it reaches critical failure if you rely on your phone for work, navigation, or emergencies. A battery at 60 percent capacity might last eight hours of heavy use but only four hours of moderate use — you cannot predict which day you will need the phone to last longer than it can. Replacing at 70 to 75 percent capacity gives you a safety margin.

If your phone is more than three years old and you plan to keep it for another two years, replacing the battery now is usually cheaper than buying a new phone later. A battery replacement at an Apple Store costs between $69 and $99 depending on your model. A new iPhone costs $800 or more. The math is straightforward.

If your phone is under warranty or you have AppleCare+, check your coverage before paying out of pocket. AppleCare+ covers battery replacement at no cost if capacity has dropped below 80 percent. Standard Apple warranty covers it only if the battery failed within one year of purchase through no fault of your own.

Where to get your battery replaced

Apple Stores and Apple Authorized Service Providers can replace your battery with a genuine Apple part. Find an authorized location by going to apple.com, clicking Support, selecting your device, and searching for "service locations." You can book an appointment online or call ahead. Replacement usually takes one to three hours, though some locations offer mail-in service if no store is nearby.

Independent repair shops and phone repair chains can also replace iPhone batteries, often faster and sometimes cheaper than Apple. The trade-off is that third-party batteries may not be genuine Apple parts, and the warranty on the repair is usually shorter. If you choose an independent shop, ask whether they use original Apple batteries or third-party equivalents, and ask what warranty they offer on the replacement.

Some people replace the battery themselves using a kit from an electronics retailer, but this requires opening the phone, which voids any remaining warranty and risks damaging the screen or internal components if you slip. Unless you have done this before, the time and risk usually outweigh the small savings.

What happens to your phone after battery replacement

After replacement, your phone will show 100 percent maximum capacity in Battery Health & Charging, and the "Condition" line will say "Normal" again. Battery life will return to what it was when the phone was new — a phone that lasted six hours on a charge will again last six to eight hours, depending on how you use it.

The new battery will degrade at the same rate as the original. You are not resetting the clock on your phone's lifespan; you are replacing one worn component. If you keep the phone for another three years after replacement, you will likely need to replace the battery again.

Your phone's other components — the screen, processor, storage — do not change when you replace the battery. If your phone was slow before replacement, it will still be slow afterward. Battery replacement solves battery problems, not performance problems.

Extending the life of your new battery

After replacement, use the same charging habits that slow battery degradation: charge to 80 percent when possible instead of 100 percent, avoid letting the battery drop below 20 percent regularly, and keep the phone cool while charging. These practices do not stop degradation, but they slow it noticeably. A battery that lasts three years with careless charging might last four years with careful charging.

Enable Optimized Battery Charging in Settings under Battery Health & Charging. This feature learns when you usually charge your phone and slows charging to 80 percent until shortly before you wake up, then charges the final 20 percent quickly. This reduces the time the battery spends at 100 percent, which is when degradation happens fastest.

Frequently Asked Questions

Can I replace my iPhone battery myself?

You can buy a battery replacement kit online, but opening an iPhone requires special tools and risks damaging the screen or internal components. Unless you have done phone repairs before, the risk of a $300+ repair mistake usually outweighs the $20 to $40 you might save. An Apple Store or authorized repair shop is safer.

How long does a battery replacement take?

At an Apple Store, battery replacement usually takes one to three hours if you have an appointment. Some locations offer same-day service if you walk in, but wait times vary. Independent repair shops often finish in one to two hours. Mail-in service through Apple takes five to seven business days plus shipping time.

Will replacing the battery fix my phone if it is slow?

No. A slow phone and a failing battery are separate problems. If your phone is slow and the battery is also degraded, replacing the battery will improve battery life but not speed. If slowness is the main problem, the issue is usually storage space, too many background apps, or an older processor — not the battery.

What if my phone shuts down at 30 percent battery?

This is a sign of severe battery degradation and replacement should happen soon. The phone is shutting down because the battery cannot deliver the power the processor needs, even though charge remains. This will get worse over time. Schedule a replacement within the next week or two.

Is it worth replacing the battery in a five-year-old iPhone?

It depends on whether you plan to keep the phone. If you will use it for another year or two, battery replacement at $70 to $100 is cheaper than a new phone. If you are considering upgrading anyway, a new phone might be the better choice. Check the cost of replacement first, then decide based on your plans for the phone.