I used the size the site recommended size after I put the info in on my body type, height and weight. If you want a little more room definitely go up a size. For me I wanted it to fit like a glove and it does exactly that. I don’t think you would want it loose cause when you crash your not going to want those pads to move. I mean that’s the thing you know you want it to fit like a glove but now if I was wearing it for casual wear yeah it needs to be a little bigger. This was a 3XL I’m 5’11” 305