I am about a size 32 in jean sizes (female) and what I would suggest is to go into the store you want to buy your panties from, buy a pair of inexpensive underwear and try those on. Or just ask the store clerk.
The reason being is that you'll probably find that each store has slightly different sizes. I usually wear Victoria's Secret and they label there's buy generic size like S, M, L, XL etc...
As a size 32, I usually would go for a M unless I'm getting a thong maybe.
Also its worth checking out the website of the store you want to buy from.
For example H&M have a size guide that might help you "translate" the size of your waist into one of their garment sizes: