Replace your iPhone battery when it no longer holds a full day of normal use, when iOS shows a battery health warning, or when the phone shuts down unexpectedly at high percentages.

Most iPhones need a battery replacement between two and three years of regular use. Apple designs batteries to retain 80 percent of their original capacity after 500 full charge cycles. Once you hit that mark, the battery degrades faster. You do not have to wait until the battery fails completely — replacing it before that point costs less and causes less disruption than dealing with sudden shutdowns or a phone that dies by midday.

The clearest signal is your phone's own battery health report. Open Settings, go to Battery, then Battery Health & Charging. If the maximum capacity reads below 80 percent, replacement will noticeably improve performance. If it reads below 50 percent, the phone will likely shut down without warning during normal use, even when the percentage display shows 20 or 30 percent remaining.

Key Takeaways

  • Check your battery health in Settings > Battery > Battery Health & Charging; if maximum capacity is below 80 percent, replacement will improve daily use.
  • Unexpected shutdowns at high battery percentages, rapid drain during light use, or a phone that dies by midday are signs the battery has degraded beyond normal wear.
  • Apple and authorized service providers replace batteries for a flat fee that varies by iPhone model, typically between $69 and $99.
  • Third-party repair shops often charge less but may use non-original parts, which can affect performance and future software updates.
  • Battery replacement takes one to three hours at Apple Stores with a Genius Bar appointment, or one to two days by mail if you use Apple's mail-in service.

Signs your battery needs replacement now

Beyond the battery health percentage, watch for three physical behaviors. The first is unexpected shutdown: if your iPhone powers off when the battery percentage shows 20, 30, or even 50 percent, the battery can no longer deliver the power the phone demands. This happens because the battery's internal resistance rises as it ages, and it cannot supply enough current all at once. Plugging the phone back in when ready turns it back on, which confirms the battery, not the logic board, is the problem.

The second sign is rapid drain during light use. If you are checking email and messages for an hour and lose 25 or 30 percent of your battery, something is wrong. Normal use should consume 10 to 15 percent per hour. Rapid drain means the battery is failing to hold its charge, even if the health percentage has not yet dropped below 80.

The third is a phone that dies by midday with moderate use. If you used to get a full day and now you are hunting for a charger by 2 p.m., the battery has degraded. This is the most common reason people replace batteries — not because the phone is broken, but because it has become inconvenient to use.

What battery health percentage actually means

The maximum capacity number in Battery Health & Charging is the percentage of the battery's original charge that it can still hold. A phone showing 85 percent maximum capacity can hold 85 percent of the charge it held when new. This is not the same as your current battery percentage — that number changes throughout the day as you use the phone.

Apple's design target is 80 percent maximum capacity after 500 full charge cycles. A full charge cycle means draining the battery completely and charging it back to 100 percent. If you charge your phone every day, you reach 500 cycles in roughly 18 months. If you charge every other day, it takes three years. The actual timeline depends on your charging habits and how much you use the phone.

Once maximum capacity drops below 80 percent, the battery degrades faster. The decline accelerates, and you may see the percentage drop 5 or 10 points in a few months. This is normal chemistry, not a defect. Replacing the battery at 80 percent is the sweet spot — the phone still works, but performance improves noticeably, and you avoid the sudden shutdowns that happen below 50 percent.

Where to replace your iPhone battery

Apple Stores and Apple Authorized Service Providers replace batteries for a fixed fee. The cost depends on your iPhone model. For current models, expect to pay between $69 and $99. Older models may cost less. You can check the exact price for your model on Apple's support website or by calling your nearest Apple Store. If your phone is still under warranty or covered by AppleCare+, the replacement may be free or discounted.

Authorized Service Providers are independent shops certified by Apple to use genuine parts and follow Apple's repair standards. They charge the same fee as Apple Stores and offer the same warranty on the replacement battery. You can find them through Apple's service locator on their website.

Third-party repair shops often charge $30 to $60 for battery replacement, which is cheaper than Apple. However, they may use non-original batteries, which can affect performance, charging speed, or compatibility with future iOS updates. Some third-party batteries also lack the safety certifications of genuine Apple batteries. If you choose a third-party shop, ask whether they use original Apple batteries or aftermarket parts, and whether they offer a warranty on the replacement.

How long replacement takes

At an Apple Store with a Genius Bar appointment, battery replacement usually takes one to three hours. The time depends on how busy the store is. You can make an appointment online or by phone. Walk-ins are accepted but may have longer waits.

If you cannot visit a store, Apple offers mail-in service. You start the process on Apple's support website, print a shipping label, and mail your phone to Apple. Turnaround is typically one to two business days once Apple receives it, plus shipping time both ways. Total time from drop-off to return is usually five to seven business days.

Authorized Service Providers have their own timelines. Some offer same-day service; others may take one to three business days. Call ahead to ask about their current wait time and whether they need an appointment.

What happens to your data during replacement

Battery replacement does not erase your data. Apple and authorized providers do not need to back up or restore your phone — they only remove the old battery and install a new one. Your apps, photos, messages, and settings remain exactly as they are. You can use your phone normally as soon as you pick it up or receive it back.

If you use a third-party repair shop, ask whether they back up your data before opening the phone. Most reputable shops do this as a safety measure, but it is worth confirming. Either way, your data should not be affected by battery replacement alone.

Battery replacement versus buying a new phone

A battery replacement costs $69 to $99 and takes a few hours to a few days. A new iPhone costs $800 to $1,600. If your phone is otherwise working well — the screen is not cracked, the logic board is not failing, and you like the model — battery replacement is almost always the cheaper choice. Even if you replace the battery twice over the phone's lifetime, you are still spending less than buying a new device.

The only reason to skip battery replacement and buy a new phone is if the phone has other damage that makes repair uneconomical, or if you want a newer model with features you need. If the battery is the only problem, replacement extends the phone's useful life by one to two years for a small fraction of the cost of a replacement.

Frequently Asked Questions

Can I replace the battery myself?

iPhones are designed to be opened only by trained technicians. The battery is glued to the case, and removing it without the right tools risks damaging the screen, logic board, or internal components. Self-repair voids your warranty and may create safety hazards. Use Apple, an authorized provider, or a reputable third-party shop instead.

Does iOS ever show a battery health warning?

Yes. If your battery health drops below 80 percent and the battery cannot deliver enough power, iOS may show a notification saying "Your battery health has degraded significantly." This is a signal to schedule replacement soon. The phone will continue to work, but unexpected shutdowns may start happening.

Will a new battery improve my phone's speed?

A new battery will not make your phone faster at processing tasks. However, it will eliminate the unexpected shutdowns and slow performance that happen when iOS throttles the processor to protect a failing battery. If your phone has been shutting down or running slowly, a new battery will restore normal performance.

How often do I need to replace the battery after the first replacement?

The replacement battery follows the same degradation curve as the original. You can expect it to reach 80 percent maximum capacity in two to three years, depending on your charging habits. Many people replace the battery once and keep the phone for another two to three years, then upgrade to a new model.

What if I ignore the battery health warning?

The phone will continue to work, but unexpected shutdowns will become more frequent and unpredictable. You may lose unsaved work, miss calls or messages, or find yourself without a working phone at an inconvenient time. Waiting also does not save money — the battery replacement cost stays the same whether you do it now or later.