HORRIBLE battery life on iPhone 4s?

I have an iPhone 4s, I've had it for a bit less than a year now. I have the newest update, iOS 8.1. I always leave my brightness on or near the lowest setting. My problem is when I go to my high school I come in with a 100% battery life, and I leave with a 10% to dead phone. My school is only 6 hours. Some rooms have Wi-Fi so I use that as much as I can. Obviously it's school so I don't use my phone a lot, study hall included I probably only use it 45 minutes at the most in school. Why does it die so damn fast and how can I fix this?

I don't know much about iphones, but my android has a 'stamina mode' which conserves battery life and switches the Wi-Fi off when the phone goes to sleep. Also you need to check whether you haven't got any apps running in the background that use a lot of power. If you are spending all day in a Wi-Fi zone and not using your phone, switch the Wi-Fi on your phone off when you aren't using it (because otherwise it will connect automatically to the internet thereby using loads of power).

It's an old phone, I have the same problem. You have to use a charger designed for an iPhone, not the iPad one. That way it won't glitch.

Change your battery at apple store. Doesn't cost alot. Make sure its "Made in china" Becouse those last longer

That's an i-phone for you.

you should switch off when you are in class, anyway.

Is it a brand new iphone 4s? If yes then Apple should replace the battery without charging anything because if it's under a year then it must be on warranty.

I think you should change your battery at the apple store. Because when I had the 4s mine lasted about 8-10 hours at school.

1. Its an older phone with a smaller battery than most other phones making the battery last a shorter amount of time
2. The parts of the phone (screen, processor, etc.) take up more battery because it is an older phone
3. A app could be taking up a lot of battery in the background, such as a game, so either delete it or remove it from multitasking (when the phone is unlocked, double press the home button and find the app and swipe up to remove it)
4. Its your fault for getting an older phone last year, suck it up (or buy a battery pack and charge it in your backpack at school)

Use it lesser than you do now… It'll probably save you some battery

The warranty is almost out by now for sure! So i'd just buy a new one off eBay for maybe $7 and replace it. Its so easy, just look on youtube and you will see someone physically guide you though it. Its a 2 minute job and well worth doing if you plan on keeping the phone.