A new iPhone battery lasts two to three years under normal use

An iPhone battery's lifespan depends on how many charge cycles it goes through, not how many months pass. Apple designs iPhone batteries to retain 80 percent of their original capacity after 500 full charge cycles. A full charge cycle means draining the battery completely and charging it back to 100 percent. Most people complete one cycle per day, so a typical iPhone battery lasts roughly 500 to 1,000 days—or about 18 months to three years—before it noticeably degrades.

The actual time varies based on your charging habits, temperature exposure, and how heavily you use the phone. Someone who charges their phone twice a day will cycle through the battery faster than someone who charges once every two days. Extreme heat or cold also speeds up degradation. By the time your battery reaches 80 percent capacity, you will notice the phone drains faster and may shut down unexpectedly even when the battery percentage shows 20 or 30 percent remaining.

Key Takeaways

  • iPhone batteries are designed to retain 80 percent capacity after 500 charge cycles, which typically takes 18 months to three years of normal use.
  • One full charge cycle means completely draining the battery and charging it back to 100 percent, not plugging in for a few minutes.
  • Charging habits, temperature, and usage intensity all affect how quickly a battery degrades—frequent charging and heat exposure speed up wear.
  • You can check your battery's current health percentage in Settings > Battery > Battery Health & Charging to see how much capacity remains.
  • Replacing an iPhone battery costs between $50 and $100 at Apple or an authorized repair shop, depending on your model.

What a charge cycle actually means

A charge cycle is not the same as plugging in your phone. One cycle equals 100 percent of your battery's capacity used, but that use can be spread across multiple charging sessions. For example, if you drain your battery to 20 percent, charge it to 100 percent, then drain it to 30 percent and charge it again, you have completed one full cycle—not two.

This distinction matters because it means you do not damage your battery by charging it multiple times per day. Charging from 20 percent to 100 percent three times in one day still counts as roughly one cycle. What matters is the total amount of capacity cycled through, not how many times you plug in the charger.

How temperature affects battery lifespan

Heat is the primary enemy of iPhone battery longevity. Lithium-ion batteries, which all iPhones use, degrade faster when exposed to temperatures above 95°F (35°C). Leaving your phone in a hot car, using it while charging in direct sunlight, or running intensive apps in warm conditions all accelerate degradation. Even brief exposure to high heat can cause permanent damage that reduces the battery's maximum capacity.

Cold temperatures also affect performance, but differently. A battery in cold conditions will report a lower charge percentage and drain faster temporarily, but the damage is usually reversible once the phone warms up. Extreme cold (below 32°F or 0°C) can cause temporary shutdown, but this does not permanently reduce capacity the way heat does. If you live in a hot climate or use your phone outdoors frequently, your battery will likely need replacement sooner than someone in a cooler environment.

Signs your battery is degrading

The first sign is usually unexpected shutdown. Your phone powers off even though the battery percentage shows 20, 30, or sometimes 40 percent remaining. This happens because the battery cannot deliver the power the phone needs at that moment, even though it still holds charge. The percentage display becomes unreliable as the battery ages.

You will also notice the phone drains noticeably faster than it used to, especially during heavy use like gaming, video recording, or navigation. Apps may close unexpectedly or the phone may slow down to preserve power. These are all signs the battery has lost significant capacity and is no longer holding a full charge the way it did when new.

How to check your battery health in Settings

Apple provides a built-in tool to see your battery's current capacity. Open Settings, tap Battery, then tap Battery Health & Charging. You will see a percentage labeled "Maximum Capacity"—this shows how much of the original battery capacity remains. A new phone shows 100 percent. At 80 percent, the battery is performing normally but noticeably degraded. Below 80 percent, you will experience the symptoms described above.

The same screen also shows "Condition" with a status like "Normal" or "Service Recommended." If it says "Service Recommended," Apple is telling you the battery should be replaced. You can still use the phone, but replacement will restore performance. If the condition shows "Unknown," the phone may have a non-genuine battery or a hardware issue that needs diagnosis.

Battery replacement costs and where to go

Apple charges between $50 and $100 to replace an iPhone battery, depending on your model. Newer models like the iPhone 15 cost more than older models like the iPhone 11. The price includes the new battery and labor. You can schedule a replacement at any Apple Store or Apple Authorized Service Provider by visiting apple.com/support or calling your nearest store.

Authorized third-party repair shops often charge less—sometimes $30 to $60—but quality varies. If you choose a non-Apple repair shop, make sure they use genuine Apple batteries or high-quality third-party batteries, not counterfeit parts. A cheap replacement battery may fail within months. Replacement usually takes one to three hours if you drop the phone off, or same-day if you have an appointment at a busy Apple Store.

How to extend battery lifespan while using your phone

Keep your phone cool. Avoid leaving it in direct sunlight, in hot cars, or in pockets during exercise. If your phone gets hot while charging, stop using it and let it cool down before resuming. Remove any thick case during charging if the phone feels warm.

Charge more frequently rather than letting the battery fully drain. Charging from 20 percent to 80 percent is gentler on the battery than draining to zero and charging to 100 percent. If you use your phone heavily, charging twice a day from 30 percent to 80 percent will extend the battery's lifespan compared to one full drain-and-charge cycle per day.

Enable Optimized Battery Charging in Settings > Battery > Battery Health & Charging. This feature learns your charging patterns and slows charging to 80 percent overnight, then tops up to 100 percent just before you wake up. This reduces the time the battery spends at 100 percent, which is when degradation happens fastest. The feature is on by default on most iPhones.

Frequently Asked Questions

Can I replace my iPhone battery myself?

You can, but it is difficult and risks damaging the phone. iPhones are glued together, and opening one requires heat, special tools, and careful technique. If you crack the screen or damage internal components, repair costs will exceed the cost of professional replacement. Unless you have experience with phone repair, professional replacement is safer and often cheaper than buying replacement parts and tools.

Does leaving my phone plugged in overnight damage the battery?

Modern iPhones have Optimized Battery Charging, which stops charging at 80 percent and waits until morning to finish. This protects the battery from spending all night at 100 percent, when degradation is fastest. If you disable this feature, leaving the phone plugged in overnight will degrade the battery faster than unplugging at 100 percent. Check Settings to make sure Optimized Battery Charging is on.

What is the difference between battery capacity and battery health?

Capacity is the total amount of charge the battery can hold, measured as a percentage of the original. Health refers to the overall condition and ability to deliver power. A battery at 75 percent capacity is still in good health, but one at 50 percent capacity is degraded and should be replaced. The Battery Health screen shows both pieces of information.

Will my iPhone slow down if the battery is old?

Yes, but only if the battery is very degraded. When a battery cannot deliver enough power, iOS automatically reduces processor speed to prevent unexpected shutdown. This slowdown is temporary and reverses once the battery is replaced. It is not permanent damage to the phone itself—only the battery needs replacement.

How much does it cost to replace an iPhone battery at Apple?

Apple charges $50 to $100 depending on your model, with newer phones costing more. The price includes the battery and labor. You can check the exact price for your model at apple.com/support or by calling your nearest Apple Store. Authorized third-party repair shops may charge less, but verify they use genuine or high-quality batteries.