I just checked and it says the battery on my iPhone 4s is 30% charged. If I leave my phone off, how much time will it have left? What if I turn it off?

I need to know if I'll be able to use this phone 6 hours later.

5 Answers 5


Turning your phone off and back on will use up unnecessary power.

Take your phone, activate airplane mode, and then lock it. If you only need to wait 6 hours, this will probably give you the most battery remaining at the end of your wait.

If your wait time were longer, turning it off might use less power than having it on the entire time, but in this case I believe the duration is short enough to not warrant a restart (which is an electronically expensive operation for most machines).


While I do not think there is any official testing data that can accurately answer your question, turning off your iPhone should more than certainly leave you with battery 6 hours later.

In the past, I've tested out the standby capabilities of both my iPhone 4 and iPhone 4S. My test consisted of charging the iPhones to 100%, switching them to Airplane Mode, and locking the screen. I left them in that state over night (about 9 hours) and checked the battery percentage. They both reported 98% to 100% capacity, which surprised me greatly.

So I would like to think that you powering your iPhone 4s for 6 hours should keep the bulk of your charge in place. Maybe left with 25% of charge.

Of course, this is all assumption ;).


So yes you should be fine letting the phone sit for 6 hours, assuming it is not doing anything else and just idling in cellular Standby mode. If you really need the phone to be ready your safest bet is to power it down, then you know its not using any power for certain.

According to Apple's Spec for the iPhone 4S it gets about these times with 100% charge so roughly 30% of these number should give a rough estimate of how much time you can you run it for with a 30% charge remaining:

Talk time: Up to 8 hours on 3G, up to 14 hours on 2G (GSM)

2.4 hours 3G, 4.2 hours 2G

Standby time: Up to 200 hours

60 hours

Internet use: Up to 6 hours on 3G, up to 9 hours on Wi-Fi

1.8 hours 3G, 2.7 hours Wi-Fi

Video playback: Up to 10 hours

3 hours

Audio playback: Up to 40 hours

12 hours

  • I just want to check to make sure. You're saying that if I leave my phone on but don't do anything with it I'll still be able to use it up to 60 hours later?
    – z-buffer
    Mar 8, 2012 at 23:00
  • If it's powered down, is the battery still being used?
    – z-buffer
    Mar 8, 2012 at 23:01
  • No zero battery is being used when its off, however the battery will still decay if left for extended periods of times, eg weeks, months, years .
    – MrDaniel
    Mar 8, 2012 at 23:07
  • 1
    Yes assuming there is nothing running on the phone thats hogging the CPU, wifi & bluetooth off eg nothing is constantly checking e-mail, no synching and no rogue background process the phone should be able to standby for about 60 hours according to Apples Specs rated numbers
    – MrDaniel
    Mar 8, 2012 at 23:15
  • How can I see what processes are running in the background?
    – z-buffer
    Mar 8, 2012 at 23:53

Hard to say, but if you are only talking a few hours, then airplane mode uses less than a couple of percent overnight for me, and will actually use less power than performing a shutdown and restart when you want it later.

  • You can talk in that mode?
    – z-buffer
    Mar 8, 2012 at 23:52

It depends! If you have app's running in the background using location based services and/or accessing network then it will be possibly out in 3-4 hours.

I would suggest you to turn off push notifications, turn off WLAN, turn off bluetooth and turn off automatic mail downloads. I would also consider shutting down apps like Facebook, Skype, Imo etc since they keep a network connection up in the background.

If I have such a low battery (and I can't recharge) I usually do shut down all running apps.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .