Bike Frame Size Converter
Find the right frame size for a road, mountain or hybrid bike from your height, and more precisely from your inside leg, in centimetres, inches and letter sizes.
About this tool
Road bikes are sized in centimetres, mountain bikes in inches or S to XL, and hybrids in either. Height gives a good first guess, and the inside leg refines it: measure from the floor to your crotch, standing barefoot against a wall with a book pressed up between your legs. The common rules are inside leg × 0.665 for a road frame in cm, × 0.225 for a mountain bike in inches, and × 0.685 for a hybrid in cm.
Brands measure frames differently, and the reach to the handlebars matters as much as the seat tube, so use this to narrow down two sizes and then try them. If you’re between sizes, the smaller frame is usually easier to adjust.