Yes it is. Your waist size is not your belt size or jeans size though, especially if you wear them on your hips which most people do these days. Your waist is above your belly button, the potentially narrow space below your rib cage.
How to Measure Your Waist
How do you measure your waist? Sounds simple enough, but it’s not always obvious where your waist is. Posture and other variables can affect the reading, so here are some basic guidelines to follow:
Position a tape measure at the narrowest point between your lower rib and the top of your hip bone, or at the midpoint in between. It should be snug but not compress the skin. If you can’t find the narrowest point (it may be difficult if you’re very overweight), measure just above your belly button.
Stand straight and breathe out normally; don’t suck in your belly.
Measure your waist first thing in the morning, before breakfast.
Though there’s no magic cutoff point, values over 37 inches for men and 32 inches for women indicate increased health risks, according to the World Health Organization; values over 40 for men and 35 for women represent substantially increased risk.