Stand upright with feet shoulder-width apart
Find the top of your hip bones and the bottom of your ribs
Place a flexible measuring tape around your bare waist at the midpoint between these points
Keep the tape level all the way around
Make sure the tape is snug but not tight
Exhale normally and relax your stomach
Read the measurement where the tape meets
Measure in inches or centimeters
Repeat the measurement once or twice for accuracy