Guides
Calculating living area under the German WoFlV
The Wohnflächenverordnung has been the usual basis for calculating residential floor area in Germany since 2004. It is short, but its three decisive rules — which rooms count, how ceiling height applies, and how outdoor space is weighted — regularly move five-figure sums.
This guide follows the calculation as it actually runs: classify rooms, record heights, apply factors, document the result. The last step is the one most often skipped and the most important when the number is later disputed.
Step 1: classify the rooms
Not every room in a dwelling is living area. Ancillary rooms do not count at all: cellars, laundry rooms, drying rooms, boiler rooms, storage outside the dwelling, loft storage and garages. A high-spec basement fit-out changes nothing about this.
Two categories are treated separately: unheated conservatories and swimming pools count at half, and balconies, loggias, roof gardens and terraces normally count at a quarter, at most at a half.
- Ancillary rooms: factor 0 (cellar, garage, laundry, loft store)
- Unheated conservatory, swimming pool: factor 0.5
- Balcony, loggia, roof garden, terrace: normally 0.25, max 0.5
- All remaining habitable rooms: weighted by ceiling height
Step 2: apply ceiling height
For the remaining habitable rooms, clear height decides. Area with a height of at least two metres counts in full. Area at least one metre and under two metres counts at half. Area under one metre does not count.
In a flat without slopes this step is trivial. In a loft conversion it is the decisive one: the footprint has to be divided into zones, and the two-metre and one-metre lines have to be genuinely measured.
Step 3: calculate and document
Multiply each part-area by its factor and add them up. The editor performs this room by room and reports raw area, factor and weighted area separately, so every line stays checkable.
Document the result so that a third party can follow it: room schedule with raw areas, factors applied, total. That schedule is what counts in a dispute — not the round number in the listing.
What the calculation does not do
An area derived from a drawing is only as accurate as the survey behind it. Where a floor area has to stand up legally — in litigation or a formal valuation — it needs an on-site survey by a suitably qualified person.
The regulation also applies directly only to subsidised housing; for privately financed housing it is normally adopted by agreement. So record in the contract which rule was applied.
Frequently asked questions
Which rooms do not count towards living area at all?
Ancillary rooms under the regulation: cellars, laundry and drying rooms, boiler rooms, storage outside the dwelling, loft storage and garages — regardless of how well they are finished.
How does a sloped ceiling affect the figure?
Through clear height. Full from two metres, half from one to under two metres, nothing below one metre. The room is divided into zones and each zone assessed separately.
Do balconies count at 25 or 50 per cent?
Normally 25 per cent. Up to 50 is permitted where the outdoor space is of particularly high quality. If you use the higher figure, be ready to justify it.
Is the editor's calculation legally binding?
It is a traceable calculation based on your inputs, not an expert report. For legally robust figures you need an on-site survey by a qualified person.