Your iPhone battery degrades over time, and you'll notice it before it fails completely

An iPhone battery loses capacity with every charge cycle—that's normal chemistry, not a defect. After about 500 full charge cycles (roughly one to two years of normal use), your battery will hold noticeably less charge than it did new. You don't have to wait for your phone to die in your hand. The signs that replacement makes sense are clear: your phone shuts down at 20 or 30 percent battery, takes hours to charge, or drains visibly while you're using it.

Apple's Battery Health feature tells you exactly where your battery stands. Open Settings, go to Battery, then Battery Health & Charging. If your Maximum Capacity is below 80 percent, your battery is aging. Below 50 percent, replacement becomes practical rather than optional—you're carrying a phone that can't hold a full day's charge.

Key Takeaways

  • Check your battery's actual health percentage in Settings > Battery > Battery Health & Charging; below 80 percent means it's degrading, below 50 percent means replacement makes practical sense.
  • Unexpected shutdowns at 20–30 percent battery, slow charging, or rapid drain during use are signs your battery is failing and should be replaced.
  • Apple's official battery replacement costs between $50 and $80 depending on your iPhone model, and takes one to three business days at most Apple Stores.
  • Third-party repair shops often charge less but may use non-original batteries, which can affect performance and future software updates.
  • If your iPhone is under warranty or covered by AppleCare+, battery replacement may be free or discounted depending on the cause.

What Battery Health percentage means

The number Apple shows you—say, 75 percent—is your battery's Maximum Capacity compared to when it was new. It doesn't mean your battery is 75 percent charged right now. It means that even when fully charged, your battery can only hold 75 percent of the energy it held on day one.

This number drops predictably. Most iPhones lose 10 to 15 percent capacity per year under normal use. At 80 percent capacity, you'll start noticing the difference—your phone might not last a full day if you use it heavily. At 50 percent, you're probably recharging twice a day or carrying a power bank. At 20 percent or lower, the phone becomes unreliable.

Apple also shows you the Peak Performance Capability status. If it says "Normal," your battery is fine. If it says "Degraded" or mentions "unexpected shutdowns," your battery needs replacement soon—not eventually, soon.

Signs your battery should be replaced now

Don't rely only on the percentage. Real-world behavior matters more. If your iPhone shuts itself down when the battery indicator shows 20, 30, or even 50 percent remaining, that's a failing battery. The phone is cutting power to protect itself because the battery can't deliver the current your processor needs, even though it has chemical energy left.

Slow charging is another clear sign. If your phone takes three or four hours to charge from empty to full, and it used to take 90 minutes, the battery is degraded. A healthy battery charges quickly at first, then slows down as it approaches 100 percent. A failing battery charges slowly the whole way.

Rapid drain during normal use—losing 10 or 15 percent battery while checking email or texting—points to a battery that can't hold its charge. This is different from heavy use draining your phone; this is the phone losing power even when you're barely using it.

How much battery replacement costs

Apple's official pricing ranges from $50 to $80 depending on your iPhone model. Older models (iPhone 11 and earlier) typically cost $50 to $65. Newer models (iPhone 12 and later) cost $70 to $80. You can check the exact price for your model on Apple's support page or by calling your local Apple Store.

If your iPhone is still under the one-year limited warranty and the battery failure isn't your fault, Apple replaces it free. If you have AppleCare+, battery replacement is free as long as the battery capacity has dropped below 80 percent. Without AppleCare+, you pay the out-of-warranty price.

Third-party repair shops—including some authorized Apple repair partners and independent shops—often charge $30 to $50. The trade-off is that they may use non-original batteries, which can affect how iOS reports battery health in future updates and may not last as long. If you choose a third-party shop, ask whether they use original Apple batteries or third-party equivalents.

Where to get your battery replaced

Apple Stores offer the most straightforward path. Walk in, explain the issue, and they'll check your battery health on the spot. If replacement is needed, they can often do it the same day if you arrive early, though it may take one to three business days depending on how busy the store is. You can book an appointment online through Apple's support site to avoid waiting.

Apple Authorized Service Providers (listed on Apple's website) offer the same service and pricing as Apple Stores. They're often faster if you live far from an Apple Store, though availability varies by location.

Independent repair shops and electronics retailers like Best Buy also replace iPhone batteries. Best Buy's Geek Squad charges less than Apple but uses third-party batteries unless you specifically request an original Apple battery (which costs more). Independent shops vary widely in price and quality—ask about their warranty on the replacement battery and whether they use original parts.

What happens during replacement

Battery replacement takes 30 minutes to two hours at an Apple Store, depending on how busy they are. The technician removes the screen, disconnects the old battery, and installs a new one. Your data stays on your phone—this isn't a repair that wipes anything.

After replacement, your Battery Health will show 100 percent (or very close to it) because you now have a new battery. Your phone will charge faster and last longer. If you were experiencing unexpected shutdowns, those will stop.

Apple's warranty on a replaced battery is 90 days. If the new battery fails within that window, they'll replace it again free. After 90 days, you're back to the standard out-of-warranty pricing if something goes wrong.

When to replace your battery before it fails

You don't have to wait for your phone to shut down unexpectedly. If your Battery Health is below 80 percent and you use your phone heavily—all day away from a charger, lots of video or gaming—replacing the battery now means you won't hit the frustrating point where your phone dies at 30 percent in three months.

If you plan to keep your iPhone for another year or two, replacing the battery at 70–80 percent capacity is practical. You'll get another year or more of reliable, full-day battery life. If you're planning to upgrade to a new phone in the next few months, skip the replacement—it's not worth the cost.

Cold weather speeds up battery degradation. If you live somewhere with harsh winters and your phone spends time in the cold, your battery may degrade faster than average. Checking your Battery Health in fall and replacing it before winter can prevent shutdowns in cold weather.

Frequently Asked Questions

Can I replace my iPhone battery myself?

Technically yes, but it's not recommended. iPhone batteries are glued in, and removing the screen requires heat and special tools. If you slip and damage the display or logic board, the repair cost jumps to $200–$400. Apple and authorized shops have the right tools and training. DIY kits cost $20–$40 but the risk isn't worth the savings.

Will replacing my battery improve my phone's speed?

Not directly. A new battery won't make your processor faster. However, if your phone was shutting down unexpectedly or throttling performance to protect a failing battery, a new battery will restore normal speed. iOS may also have been limiting performance to extend battery life—a new battery removes that need.

What if my battery health is at 85 percent but my phone still dies at 20 percent?

That's a sign of a failing battery even though the health percentage is still decent. The battery can't deliver power reliably under load. Take your phone to Apple or an authorized repair shop and show them the Battery Health reading along with the shutdown behavior. They can run diagnostics to confirm whether replacement is needed.

Does replacing the battery affect my warranty?

No. Battery replacement doesn't void your warranty on the rest of the phone. The replaced battery itself has a 90-day warranty from Apple. Your phone's original one-year limited warranty (or AppleCare+ coverage) continues on everything else.

How often will I need to replace my battery?

Once every two to three years if you use your phone daily. If you use it lightly or charge it less frequently, you might go three to four years. The battery will degrade whether you replace it or not—it's just a matter of when the degradation becomes annoying enough to warrant the cost.