A yellow battery icon means your iPhone is in Low Power Mode

When your iPhone's battery icon turns yellow instead of green or red, your phone has entered Low Power Mode. This is not a warning that something is broken — it is a setting your iPhone turned on automatically when the battery dropped to 20 percent, or one you switched on yourself through Settings.

Low Power Mode reduces how hard your phone works. It slows down performance, limits background activity, and dims the screen slightly. The yellow color is straightforward the visual signal that this mode is active. Your phone will stay in Low Power Mode until you charge it above 80 percent, or until you turn the mode off manually.

Key Takeaways

  • A yellow battery icon means Low Power Mode is on, which happens automatically when your battery reaches 20 percent.
  • Low Power Mode slows your phone's performance and reduces background activity to extend battery life.
  • You can turn Low Power Mode off at any time by going to Settings > Battery > Low Power Mode, even if your battery is low.
  • The yellow icon disappears once you charge your phone above 80 percent or manually disable Low Power Mode.
  • Low Power Mode does not damage your battery or phone — it is a normal feature designed to help you use your phone longer between charges.

How Low Power Mode activates automatically

Your iPhone is set by default to turn on Low Power Mode when the battery level hits 20 percent. You do not have to do anything — the phone makes this choice on its own. At that point, the battery icon turns yellow and you will see a notification on your screen saying Low Power Mode is on.

If you have an older iPhone model, Low Power Mode may set up at 20 percent. On newer models with larger batteries, you may see it set up at a slightly different threshold, but 20 percent is the standard. Once Low Power Mode is on, your phone will not turn it off until you manually disable it or charge the battery above 80 percent.

What Low Power Mode actually does to your phone

Low Power Mode makes several changes to how your iPhone runs. It reduces CPU and GPU speed, which makes apps open and run slower. It turns off or limits background app refresh, so apps are not checking for updates when you are not using them. It reduces mail fetch frequency, meaning your email will not arrive as quickly. It also dims the screen and may reduce animation smoothness.

These changes are not permanent damage — they are temporary adjustments that last only while Low Power Mode is on. Once you turn it off or charge your phone, everything returns to normal speed and behavior. The trade-off is that your battery lasts much longer. A phone in Low Power Mode can often run for several more hours on the same charge.

How to turn off Low Power Mode manually

You can turn off Low Power Mode at any time, even if your battery is still low. Open Settings, tap Battery, then tap Battery Health & Charging. You will see a toggle for Low Power Mode — tap it to turn it off. The yellow battery icon will disappear when ready and your phone will return to full speed.

You can also turn Low Power Mode off from Control Center. Swipe down from the top-right corner of your screen (or up from the bottom on older iPhones), find the battery icon, and tap it. The icon will turn green or red depending on your actual battery level, and your phone will stop limiting performance.

Why your phone turned on Low Power Mode without you asking

If you did not manually turn on Low Power Mode, your battery level almost certainly dropped to 20 percent or lower. This is the automatic trigger. Your phone is designed to protect its own battery life by activating this mode when power runs low, the same way a car's fuel gauge warns you before you run out of gas.

Some older iPhones with degraded batteries may set up Low Power Mode at higher battery levels — sometimes at 30 or 40 percent instead of 20. This happens because the phone's battery health has declined and it cannot deliver power as reliably. If Low Power Mode keeps turning on when your battery is above 20 percent, your battery may need service. You can check battery health in Settings > Battery > Battery Health & Charging.

The difference between yellow, green, and red battery icons

Your iPhone uses three battery icon colors to tell you the state of your charge. Green means your battery is above 20 percent and Low Power Mode is off — your phone is running at full speed. Yellow means Low Power Mode is on, usually because your battery is between 1 and 20 percent. Red means your battery is critically low, usually below 5 percent, and your phone may shut down soon.

The color change is purely informational. It does not mean your phone is damaged or that you have done anything wrong. It is straightforward a quick visual way to see your power status without opening Settings or looking at a percentage number.

Low Power Mode and battery health

Using Low Power Mode does not harm your battery or shorten its lifespan. In fact, it may help preserve battery health because it reduces the strain on the battery by lowering power demand. Batteries degrade over time with every charge cycle, but Low Power Mode does not accelerate that process — it slows it down by reducing how hard the battery has to work.

If you are concerned about your battery's long-term health, you can check it in Settings > Battery > Battery Health & Charging. This screen shows your maximum capacity — the percentage of the battery's original charge that it can still hold. A new iPhone typically shows 100 percent. Over time, this number drops. When it falls below 80 percent, your phone may set up Low Power Mode more often, but this is normal aging, not damage caused by using Low Power Mode.

Frequently Asked Questions

Can I stop Low Power Mode from turning on automatically?

No, you cannot disable the automatic trigger entirely. When your battery reaches 20 percent, Low Power Mode will turn on. However, you can turn it off manually at any time by going to Settings > Battery > Battery Health & Charging and toggling Low Power Mode off. You can also turn it on manually before your battery gets low if you want to extend your usage time.

Does Low Power Mode slow down my phone permanently?

No. Low Power Mode only slows your phone while it is active. Once you turn it off or charge your battery above 80 percent, your phone returns to full speed when ready. There is no lasting effect on performance.

Why does my battery reach 20 percent so quickly?

This usually means you are using your phone heavily — streaming video, playing games, or running multiple apps at once all drain the battery faster. It can also mean your battery health has declined. Check Settings > Battery > Battery Health & Charging to see your maximum capacity. If it is below 80 percent, your battery may not hold a charge as long as it used to.

Is the yellow battery icon a sign my phone needs repair?

No. The yellow icon straightforward means Low Power Mode is on. However, if Low Power Mode turns on when your battery is above 20 percent, or if your battery drains unusually fast, your battery may need service. Visit an Apple Store or authorized repair center to have your battery health checked.

Can I use my phone normally while Low Power Mode is on?

Yes, but it will be slower. Apps will take longer to open, websites will load more slowly, and animations will be less smooth. You can still make calls, send messages, take photos, and use any app — nothing is blocked. The slowdown is usually noticeable but not severe, and it is worth the trade-off if it means your phone lasts several more hours.