That depends on the bread size? From a quick survey of bread recipes online, you need flour and water in a ratio of about 2:1 to 2:1.5. So 1kg of flour gives 1.5kg–1.75kg of dough. I don’t know how much water evaporates during backing, but I think an end product of 1.25kg–1.7kg is a reasonable guess. That’s about a standard sized loaf (to me).