OMG. My waist is 36.5 inches and I ordered this waist trainer in size Large. It fits AMAZING! When I say my waist is snatched, I mean it is snatched. 1st I purchased size XL, it fit but it wasn't snug. I was able to go to the 3rd (tightest) prong with the 1st wear, so I wasn't getting optimal results. This Large size is perfect!! Great quality. I highly recommend this waist trainer.