Floor plan for single-family house 7x12m

7*12 is 84 sqm for me. If you plan 40-50 sqm for the living room/kitchen/dining area, then there would still be about 25 sqm left for mom and dad. In the maxi version, nearly 10 sqm would remain for the hallway, guest WC, and wardrobe. Not everyone has to plan such a monstrous bathroom like we do :P

12/13 sqm are already used up by the exterior walls ...

Roughly factor 0.78. When trying to squeeze in many rooms, rather lower. More than 65sqm of living space per floor will not be found. Maybe a bit more downstairs (open layout), rather less upstairs

Our building plot was not particularly large either... in the end, we built 7.70m x 11.20m (minus 32cm wall construction on each side... so inside probably rather 7.05m x 10.55m with 1.30m knee wall.

We then have a total of 130 sqm of living-use area (so without sloping ceilings) and 138 sqm of floor area (with sloping ceilings).

However, we only planned/built 2 children's rooms.