Tried to work out the size of the console by using the controller as scale.
Xbox One Dimensions = 7208cm3 = 33.3cm x 27.4cm x 7.9cm
Xbox One S Dimensions = 4342cm3 = 29.5cm x 23cm x 6.4cm
Xbox One X Dimensions = 4320cm3 = 30cm x 24cm x 6cm
Xbox Series X Dimensions = 6570cm3 = 29.2cm x 15cm x 15cm
So in terms of volume it's smaller than the OG XBO, a fair bit larger than the XBO S/X.