What is the internal height of a medium height Fiat Ducato?

I am 1m 90cm in height and am thinking of buying a Fiat Ducato/Renault Master. I want to be able to stand upright without having to bend my head in order to do so. Looking at the vans for sale it seems that there are three different heights: the low height and what is often referred to as 'hi-roof' but is lower than others also called 'hi-roof'. All very confusing!