How to know when your iPhone battery is failing
Your iPhone battery is failing when it no longer holds a charge through a normal day of use, shuts down unexpectedly even when the battery percentage shows 20 or 30 percent remaining, or takes much longer than it used to between charges. These are the three clearest signs that the battery itself—not your usage habits or a software problem—has degraded enough to need replacement.
iPhones use lithium-ion batteries that lose capacity over time. Apple's own data shows that after 500 complete charge cycles (a full drain and recharge), most iPhone batteries retain about 80 percent of their original capacity. After 1,000 cycles, they typically hold 60 to 70 percent. A charge cycle is counted each time you use 100 percent of the battery's capacity, whether in one sitting or spread across multiple partial charges throughout the day.
The battery degrades whether you use the phone or not—age matters as much as use. An iPhone that sat in a drawer for three years will have a weaker battery than one actively used for one year, even if the unused phone has fewer charge cycles.
Key Takeaways
- Replace your battery when the phone shuts down unexpectedly, drains faster than normal, or no longer lasts a full day of typical use.
- iPhones typically need battery replacement between two and three years of regular use, though this varies based on how often you charge and environmental conditions.
- You can check your battery's current health percentage in Settings > Battery > Battery Health & Charging on any iPhone running iOS 16 or later.
- Apple and authorized repair shops replace batteries for a set fee; third-party repair shops may charge less but may not use Apple parts or provide the same warranty.
- Replacing the battery is usually faster and cheaper than replacing the entire phone, even for older models.
Check your battery health percentage in Settings
iPhones running iOS 16 or later show you a number that represents your battery's current health. Open Settings, tap Battery, then tap Battery Health & Charging. You will see "Maximum Capacity" as a percentage—this is how much charge your battery can hold compared to when it was new.
A battery at 80 percent capacity is still usable, but you may notice the phone drains noticeably faster than it did when new. At 70 percent or below, most people find the phone unreliable for a full day without charging. At 50 percent or lower, the phone may shut down without warning even when the battery percentage display shows 20 or 30 percent remaining.
If your iPhone is older than iOS 16, you cannot see the exact percentage, but you can still observe the symptoms: unexpected shutdowns, rapid drain, or the phone dying before the battery icon reaches zero. These are reliable signs the battery has degraded significantly.
Timeline: when batteries typically need replacement
Most people need to replace an iPhone battery between 18 months and three years of regular daily use. The exact timing depends on how you charge the phone and the environment where you use it.
Batteries degrade faster if you regularly let the phone drain completely before charging, charge it in very hot conditions (above 95°F), or leave it plugged in overnight constantly. Batteries last longer if you charge the phone when it reaches 20 to 30 percent rather than waiting until it dies, keep the phone in moderate temperatures, and unplug it once it reaches 100 percent.
An iPhone used lightly—checked a few times a day—may go three to four years before needing replacement. An iPhone used heavily—constant texting, video, gaming—may need replacement in 18 months to two years.
What to expect from an Apple Store or authorized repair shop
Apple and Apple-authorized repair shops replace iPhone batteries for a flat fee that varies by model. As of 2024, the fee ranges from roughly $70 to $100 depending on the iPhone model, though this varies by location and changes over time. The repair usually takes one to three hours if you drop the phone off, or you can make an appointment for an in-store replacement that may take 30 minutes to an hour.
Apple uses genuine Apple batteries and provides a 90-day warranty on the replacement battery. If the new battery fails within that period, they will replace it again at no cost. The phone's water resistance is maintained because Apple has the tools to properly reseal the device after opening it.
You can check the current fee for your specific iPhone model and make an appointment through Apple's website or by calling your local Apple Store.
Third-party repair shops and mail-in services
Independent repair shops and mail-in battery replacement services often charge $30 to $60 less than Apple. However, they may not use genuine Apple batteries, and the warranty on the replacement battery is typically shorter—often 30 days instead of 90 days. Some third-party shops do not properly reseal the phone, which can affect water resistance.
If you choose a third-party shop, ask whether they use Apple batteries or third-party batteries, what warranty they provide, and whether they test water resistance after the repair. Read recent reviews from other customers about the quality of their work.
Mail-in services require you to ship the phone to them, wait for the repair, and have it shipped back—usually five to ten business days total. This is useful if no local repair shop is available, but it means you are without the phone during that time.
When to replace the whole phone instead of just the battery
If your iPhone is more than five years old and the battery is failing, consider whether the phone has other problems: a cracked screen, a camera that does not work, a speaker that is muffled, or a home button that is unresponsive. If you are paying for battery replacement and the phone has multiple other failing parts, the total repair cost may approach the cost of a used replacement phone of the same model or a newer refurbished model.
If the phone is working well otherwise and the battery is the only issue, replacement is almost always cheaper than buying a new phone. Even a battery replacement at Apple's full price is a fraction of what a new iPhone costs.
Frequently Asked Questions
Will replacing the battery make my iPhone feel like new?
It will feel noticeably faster and more responsive because the phone will no longer slow itself down to prevent unexpected shutdowns. Battery replacement restores the phone's performance but does not change the speed of the processor or the amount of storage. If the phone felt slow for other reasons—too many apps running, low storage space—those problems remain after battery replacement.
Can I replace the battery myself?
You can buy a replacement battery and tools online, but opening an iPhone requires removing the screen, which is difficult without the right equipment and can easily crack the screen or damage internal components. If you damage the phone during the repair, the cost of fixing it usually exceeds what you would have paid for professional replacement. Unless you have experience with phone repair, professional replacement is the safer choice.
What happens to my data when the battery is replaced?
Your data stays on the phone. Battery replacement does not erase anything. However, you should back up your phone before any repair in case something unexpected happens. You can back up to iCloud through Settings > [Your Name] > iCloud, or to a computer using Finder or iTunes.
Is it normal for a new battery to drain quickly at first?
A new battery may show unusual drain for the first few charge cycles as the phone recalibrates its battery percentage display. If the drain continues to be abnormal after five or six full charge cycles, contact the repair shop or Apple to discuss a warranty replacement.
Can I use my iPhone while it is being repaired?
No. The phone must be powered off and opened to access the battery. If you need to use your phone during the repair, bring a second device or plan the repair for a time when you can be without it. Mail-in services take five to ten days, so plan accordingly.