Low Power Mode slows charging, not speeds it up

No. Low Power Mode does not make your iPhone charge faster. It does the opposite — it can actually slow down charging slightly because the phone limits background activity and processing power to preserve battery life. Low Power Mode is designed to extend how long your current charge lasts, not to speed up the charging process itself.

The confusion often comes from mixing two separate things: how fast the phone charges from empty to full, and how long the charge lasts once you have it. Low Power Mode helps with the second one. If you want faster charging, you need to look at the charger itself, the cable, and the phone's charging hardware — not at software settings.

Key Takeaways

  • Low Power Mode reduces power consumption while the phone is in use, but does not affect how fast electricity flows into the battery during charging.
  • iPhone charging speed depends on the wattage of your charger, the quality of your cable, and whether the phone is actively being used while plugged in.
  • Using a higher-wattage charger (20W or above for most iPhones) will noticeably reduce charging time compared to the standard 5W charger.
  • Turning off Low Power Mode before charging, or leaving it on, makes no meaningful difference to how quickly your battery fills.

What actually determines iPhone charging speed

Your charger's wattage is the primary factor. Apple's standard charger for most iPhones is 5W, which charges slowly. A 20W charger (widely available and inexpensive) will charge most modern iPhones roughly four times faster. A 30W or higher charger will charge even faster, though the phone itself has a maximum charging speed it will accept — going beyond that does not help.

The cable matters too. A damaged or low-quality cable can reduce charging speed or prevent fast charging entirely. Apple's USB-C to Lightning cables support fast charging, but older Lightning cables may not. If you are using a third-party cable, check that it is rated for the wattage of your charger.

What you do while charging also affects speed. If you are actively using the phone — scrolling, gaming, streaming — the processor is drawing power at the same time the battery is being filled. This creates heat and slows the charging process. Putting the phone in airplane mode or straightforward setting it down unused will let it charge faster than using it while plugged in.

Why Low Power Mode does not speed up charging

Low Power Mode works by limiting what the phone does in the background: it reduces frame rates, delays email fetches, turns off location services, and caps processor speed. These changes preserve battery life when you are using the phone on its current charge. But they do not change the electrical circuit that moves power from the charger into the battery.

The charging circuit operates independently of Low Power Mode. Whether Low Power Mode is on or off, the same amount of electrical current flows into the battery at the same rate. The only time Low Power Mode touches charging is if you have enabled the "Optimized Battery Charging" feature, which intentionally slows charging to 80% to extend the battery's lifespan over years — but that is a separate setting, not part of Low Power Mode itself.

When Low Power Mode actually helps with battery

Low Power Mode is useful if you are away from a charger and need your phone to last longer. If you turn it on when your battery is at 20%, you might stretch that remaining charge from two hours of normal use to four or five hours. That is valuable if you are traveling or stuck somewhere without access to power.

But if your phone is plugged in, Low Power Mode serves no purpose. The charger is continuously refilling the battery, so the power-saving features have nothing to save. You can leave Low Power Mode on while charging without any harm, but it will not make the charging any faster.

The fastest way to charge an iPhone

Use a 20W or higher USB-C power adapter with an appropriate cable. Plug the phone in and do not use it while it charges. If you want to use the phone, put it in airplane mode to reduce power draw. Turn off Low Power Mode if it is on — not because it slows charging, but because you do not need it when the phone is plugged in.

If your iPhone is hot to the touch while charging, unplug it and let it cool. Excessive heat slows charging and damages the battery over time. This can happen if you are using the phone heavily while charging, or if the charger or cable is faulty. A phone that is straightforward warm is normal; one that is too hot to hold comfortably is a sign something is wrong.

Checking your current charger wattage

Look at the text printed on your charger brick. It will say something like "5W", "20W", "30W", or "USB-C Power Adapter 20W". If you do not have the original charger or cannot find the wattage, you can check what charger your iPhone model shipped with by looking up your model on Apple's website.

If you have a 5W charger and want faster charging, buying a 20W USB-C charger is the single most effective upgrade. They cost between $15 and $30 and will cut your charging time roughly in half. Make sure the cable is also USB-C to Lightning (or USB-C to USB-C if your iPhone is a newer model with USB-C).

Frequently Asked Questions

Does Low Power Mode drain the battery faster when charging?

No. Low Power Mode has no effect on charging speed or battery drain while the phone is plugged in. The charger supplies power continuously regardless of what software settings are active.

Will turning off Low Power Mode make my iPhone charge faster?

No. Low Power Mode does not affect charging speed in either direction. You can turn it off, leave it on, or toggle it while charging — the charging time will be the same.

Can I use my iPhone while it charges in Low Power Mode?

Yes, but the phone will charge slower if you use it heavily, because the processor is drawing power at the same time. Low Power Mode reduces that drain slightly, but the effect is minor compared to straightforward not using the phone while it charges.

What if my iPhone is charging very slowly?

Check your charger wattage first — a 5W charger is much slower than a 20W one. Then inspect the cable for damage and try a different cable if you have one. If the phone is hot, unplug it and let it cool. If it still charges slowly with a known-good charger and cable, the charging port or battery may need service.