Whether you have big feet or small feet, usually Palladium boots are true to their size. I am talking from first-hand experience.
Check out this video review that someone made on Youtube.
Most of the Amazon reviews state that the boots fit accordingly to their size. Depending on the product 70-80% of people said the size was exactly as described, so that is actually a good number!
If I am uncertain about the size, I usually get slightly bigger size and just put insoles (which fill out shoe), and they make you slightly taller as well 😉