Replying to Saga's Fatigue 2L Pant Sizing?

On Saga's website, it gives a half waist of 17.5 inches, and I'm really not sure how to translate this into waist size. I want to go with a size medium because I do not want a ton of bagginess, but I do not want to have the waist too tight on me. I would much rather have it larger. I tried on a size large, and my waist was obviously too small by 2-4 inches guesstimate, but does anyone know how much they differ from size to size?

Specs:
5"11
160lbs
Normal waist size for pants: 32

+K to any helpful answers, cheers.