How do you calculate “accurately” then? I’d be curious because I’ve only ever used the online calcWith a Grizzly Stik 320 at 29” and a 125 Samurai mine are ~525 and measured them at 18% I think it was. Like mossy said, it’s easy to measure, don’t go by the calculator if you’re wanting an accurate number on your arrows. The calculator is better used for comparison shopping IMO