Is this normal Galaxy S3 battery life?

[A]

Finished charging at 100% last night at 1ish AM.
Sat idle until I woke up at 8:30 AM (and then, when I woke up, battery was about 85%).
I've been at work for most of the day, so I didn't even use my phone much besides about 15 minutes of video watching on YouTube; maybe 30 minutes of Facebook/Tumblr/Twitter usage combined; about 15 min of texting.
It's 6:30 PM now, and my phone has 33% battery life left. The screen on time is only at 1 hr 5 min now.
Is this average battery life? Or is there something defective with my battery that I should have checked out? I just think I should have more battery life left if I haven't been using it much today.

[ThrashDrummer17]

I also own the Galaxy S3 and this seems fairly normal to me. I don't even leave my phone on when I sleep, but when it's on throughout the daytime, I find that I gotta charge it at least once a day.

[Robert]

You can extend your battery life by turning off things you don't need on. Such as the Wi-Fi and GPS, these use up a lot of battery power.
Also several programs/apps will continuously run in the background use up battery power, such as the Weathernetwork app that shows current weather conditions.
If you go to the task manager, and end programs and clear the RAM, it will shut down some of these programs. Otherwise you will have to remove some programs from the main menu pages as they might be running live that way (like the weathernetwork app).

The SIII is supposed to, in ideal conditions will have 20+ hours of standby time, but this is only an average, depending on what programs and apps you are running.