For best fit and your satisfaction, you can measure your best fitting similar shorts and compare it to the measurements below:
Measurements on flat surface, not stretched:
16" Chest - Measured from armpit to armpit.
14" Waist - Hip to hip, across waist
14" Rise - From top of waist to crotch stitch.
20" Inseam - From crotch stitch to end of bottom hem.
48" Overall Length - From shoulder to hem.
Measurements shown in pictures.