Planning laws also define the extent to which a plot may be utilised in terms of a percentage ratio; for example, the W2/25 Zone regulations permit owners of plots of 1000m2 to construct 250m2 of living space over 2 main floors.

Accordingly, 25 equates to 25%. It is advisable to make a detailed inspection of local planning laws.

Depending on the municipal authority and canton, development ratios can be given terms of HNF (Hauptnutzfläche or primary living space), GF (Geschossfläche or number of floors), or BGF (Bruttogeschossfläche or total floor space).