The size of a high school football is a Wilson TDS.
11.6 inches long, with a diameter of 6.7 inches.
Well it all depends like the size of the school, how good you football team is, and how many people are involved. You can have as little as 23 players on your roster. Or you can have as many as 93 players on your roster depending. IMPROVED ANSWER: I think you mean't the size of the football itself and not the size of a team.....all NHFS footballs must meet the minimum size requirements for High School play. The patterns and "girth" of the ball my slightly be different...but all in all, you want a ball stamped with the NHFS seal. Then you know you are playing with an official ball.