What size breech does this translate into?

I have a pair of large irideon breeches that are great, but their falling apart so I need some new ones. I was looking in the closeout sections of dover smartpak etc. and I can't find the same ones, so I need to know what size these would be. I was thinking I would need a 32 or 34 possibly a 36 but idk which one is more accurate I wear like an 11/12 pant size. any help would be greatly appreciated. thanks