You can make small spaces work if necessary.
We (myself and seven children) are in a tiny 4 bedroom house. The whole house is 7.5m x 9.5m.
The three eldest (18yo, 16yo, 13yo) have their own rooms: 2.7m x 3.2m each.
The next two (11yo, 9yo) share the lounge room, partitioned off by furniture: 4m x 5m.
The two youngest (5yo, 3yo) share the master bedroom: 3.2m x 3.3m.
I have the laundry: 1.55m x 2.7m (including the hot water system and laundry tub)
We also have a dining area 6m x 3m
And a kitchen (I've forgotten the dimensions).
My father is visiting at the moment, so he is in the master bedroom with the two youngest.