probably around 300 caloriesdon t worry about your weight at your age because you re about to grow taller and go through pubertyAlso check out this blog for great advice on nutrition and fitness:http://mytotalfitness.blogspot.com/http://thegreatbookmarks.blogspot.com/
Mark, this page has a link that you re going to love! http://www.easy-weightloss-tips.com/burn��The link is a site where you put in your weight and minutes and it gives you the number of calories that you burn for about 100 activities, including the bike. When you go to this page, if you look around, you ll see tons of weight loss tips, as the site is called Easy Weight Loss Tips. Under the Exercise Plan tab, you ll see a page for the stationary bike too. Enjoy!