Can I still track my Iphone if I don't have the app?

My phone got stolen, I don't have the find my iphone app installed but I logged into icloud and I can see my phone among the devices but it's offline. My phone can't be turned off because the sleep button doesn't work and the battery was almost full when it got stolen which wasn't that long ago. It does have a passcode but I'm worried sick that the person that stole it has something evil in mind ( like looking at my pictures or my personal details etc.) This happened at school so it's very likely that a teenager stole it and another girl got her phone stolen (our purses were in the changing room and someone went in and stole them). If I remember correctly, I had the find my iphone option turned off in settings because I was trying to save battery and I don't even have the app installed. So I guess my question is can I track it if the thief connects to Wi-Fi or not?

There's no "app", exactly, for "Find my iPhone".

In the iPhone, there's a Settings icon. In Settings, under iCloud, along with a bunch of other items is a switch where Find My iPhone can be on or off. Assuming your AppleID is associated with the iPhone AND the Find My iPhone service for iCloud is on, then when the iPhone is turned on, if there's any Wi-Fi or cell sevice available, the location can be tracked.

Since you said you turned Find My iPhone off, then the location information can't be transmitted and even if the iPhone is on, the location information will not be sent even if Wi-Fi is available - you told it not to send the information when you turned that setting off and it will always appear as offline until Find My iPhone setting is turned on.

If just turned it on you could remotely lock it, remotely wipe it, locate it, and put a permanent msg on it. Since you were to lazy to turn it on, consider it gone and move on. Its theirs now, you made it easy for them.

Well if you signed into your Apple ID in icloud and turned find my iphone on you can still track with icloud.com. The find my iphone app is to track via an IOS device yours and other devices on the same Apple ID.

If the device is offline it can't be tracked. It meas either the phone is out of service, the phone has been turned off or the battery is depleted.

If you do not have find my iphone, it is better for you to contact your service provider and see if they can help. To prevent your new idevice from being stolen or lost in the future, I suggest you apply some free anti-theft apps like iLostFinder ( http://ikeymonitor.com/free-apps ) except set up Find My iPhone/iPad/iPod in iCloud on the device. It will take pics of the thief or finder when she/he tries to open your device with a wrong pass and then send the pics to your email etc. Hope it helps.

You can't unless you registered findmyiphone app.