Unfortunately, bike sizes vary from brand to brand. A few years ago, the XL of one mid-sized brand was smaller than the Small of another mid-sized brand. Think of it like clothing: you may fit a Small in some American brands and you could be an Asian XL.
Your first point of reference is the "Reach" measurement. This doesn't tell the whole story of a bike's fit, but it's the fastest way to get close.
Depending on how you like a bike to feel, something in the range of 440 mm - 480 mm should be about right. This will typically be a Large.