You want to take you inseam X .59 for a mountain bike and your inseam X .65 for a hybrid or a road bike. You also want a stand over clearance of 2-4 inches on a mountain or a 1-2 inches on a road bike. You want a wheel size of 26" or 700c. Frame sizes are measured from the center of the crank to the top of the seat tube where the clamp is.