The Emperor of Mankind is a fictional character from the Warhammer 40,000 universe, which is a tabletop wargame and science fantasy franchise. As a fictional character, the Emperor's height is not specifically defined in the official lore or source material.
However, in various artistic depictions, the Emperor is often portrayed as an immensely tall and imposing figure, towering over regular human characters. His height is typically depicted as much taller than an average human, emphasizing his status as a god-like being and the ruler of the Imperium of Man.
Keep in mind that artistic interpretations and descriptions of fictional characters can vary across different sources, adaptations, and illustrations, so there is no universally agreed-upon height for the Emperor of Mankind.