The ad says to order the same size as the waistband. I have a hard time finding the right pieces so I was a bit worried but I wear a 50 waist so I bought a 50 belt. The belt was insanely long. I ended up cutting off a foot or two and it's still long enough. If you don't see your size, just buy it, it will fit easily. It does slip a bit, but other than that it's the best belt I've ever had. If I can get a hold of it, it's the only strap I've had that really holds my pants and is really secure.