Forensic scientists can estimate a person's height from the length of his femur bone. A person's height is a little less than two times the length of his femur bone. Most people think you measure leg length from the groin area to the bottom of the foot. That is not the case. The leg actually starts below the belly button and ends at the ankle. With a helper, it's fairly easy to calculate the length of your legs.
Lie face up on a flat surface like a table. Your spine lies flat. Do not bend to one side. Keep your spine, torso and legs straight.
Raise your legs toward the ceiling. Your buttocks should lift off the surface. Place your legs back on the flat surface.
Place the end of a tape measure at the bottom of your belly button. Ask someone to pull the tape measure until it reaches the middle of your right ankle. The tape measure should be parallel to the right ankle bone.
Calculate the length of your leg using the measurement in Step 3.
Repeat the steps above to calculate the length of your left leg. In Step 3, have your helper pull the tape measure until it reaches the middle of your left ankle.
Do not be alarmed if your legs are slightly different lengths. You might want to consult a chiropractor if there is a large discrepancy that could affect other parts of your body.