Waist is measured at the narrowest level of the torso
Hip is measured at the fullest level of the glutes

Swim briefs are meant to cover around the hip area, therefore, honor your hip measurements more than waist while you choose the right size for yourself.

Example A - Waist 30 1/2", Hip 38 1/2":
- Waist is S
- Hip is M
- Therefore, size M will likely fit better.
- If waist is a bit loose, simply tightening drawstring a bit

Example B - Waist 31 1/2", Hip 37"
- Waist is M
- Hip is S
- Therefore, size S will likely fit better
- Waist will be fine to stretch a bit to fit

Example C - Waist 33", Hip 39 1/2"
- Both waist and hip are right between M and L
- If you want the fit to be more relaxed, then pick L
- If your main activity is to swim, then pick M, since everything fits slightly loser in the water

If you are still unsure, feel free to email us at info@kovarx.com