Stand up and move any clothing or other impediments out of the way of your waist, which is located in the space between your bottom rib and hip bone.
Estimate the circumference. Take a piece of string and hold one end of it against your stomach with your left hand. Wrap the string around your waist and with the fingers of your right hand, mark the place where the string meets.
Measure the string. Remove the string from around your waist and lay it on a table. Using a ruler, measure the distance from the end of the string to the place you marked. This will be the approximate circumference of your waist.