How many calories? 13 yr old boy.

Hi,

I'm a 13 yr old boy (14 in November) and I wonder how many calories I need!

My stats:

Waist (at navel): 25.6 inches (65cm)
Waist (at narrowest point): 24.5 inches (62cm)

Weight: 113.5 pounds (51.5 kg)
Height: 5' 5.3" (166cm)

I train strenght training 3 times a week, and I walk for 30 minutes 3 times a week. I have a normal lifestyle with school, freinds ++.

How many calories do I need a day?

Thanks appletwo. 

How much do you guys think I burn when I ride my stationary bike at 25-28 mph per hour? (yes, I know it's extremely fast )

Teenage boys are notorious for their appetite.  Just eat!  3,000-5,000 calories sounds perfectly reasonable to me, especially if you're trying to gain.  My very thin, 5'7 (male) friend consumes at least 1,800 calories a day in just juice!  Plus plenty of real food, obviously.  I wouldn't worry so much about how many calories this burns, or how many are in that...  Just play it by ear, you don't wanna develop an obsession about it 'n stuff.