To determine your correct frame size,
The size chart below shows measurements for two frame types, Conventional and Compact type frames. Conventional frames are frames with a straight Top Tube (crossbar) and Compact frames are frames with a sloping Top Tube.
Measure your inseam in centimeters (crotch-to-floor measurement without shoes). Multiply the distance by .65 to determine conventional frame size (to convert inches to centimeters, multiply inches by 2.54). Find the equivalent Compact frame size from the chart below.