The size of the hybrid bike you choose should be based on your height. When standing over the frame of your bike, make sure there's at least a 2-centimeter gap between you and the top tube. Find your height below to determine what size male/unisex frame you need: 4'10" to 5'2" - choose an extra small bike with a 13"-14" frame 5'2" to 5'6" - choose a small bike with a 15"-16" frame 5'6" to 5'10" - choose a medium bike with a 17"-18" frame 5'10" to 6'1" - choose a large bike with a 19"-20" frame 6'1" to 6'4" - choose an extra large bike with a 21"-22" frame 6'4" to 6'6" - choose an extra extra large bike with a 23"-24" frame Women's hybrid bikes tend to be shorter in length with narrower handlebars and smaller frame sizes. In some cases women's hybrid bikes have a step through frame where the top tube drops down much lower. Find your height below to determine what size women's frame you need: 4'10" to 5'2" - choose an extra small bike with a 13"-14" frame 5'2" to 5'6" - choose a small bike with a 15"-16" frame 5'6" to 5'10" - choose a medium bike with a 17"-18" frame 5'10" to 6'1" - choose a large bike with a 19"+ frame