To measure waist size, take a tape measure and circle it around the waist in a straight line just at the level of the hip bones, starting at the navel and ending at the navel. Don't hold your breath or hold the tape too tight while measuring.
The tape measure should have inch or centimeter marks to show an accurate measurement. To maintain health, women's waists should not measure more than 35 inches, according to WebMD. Men's waists should measure no more than 40 inches. Waist size can indicate risk for diabetes, heart disease, high blood pressure and high cholesterol.