Calculating floor area: what counts and what does not
Floor area enters almost every rent calculation: reference rent, rent brake, service charges and heating costs.
Checked by Radif Partners · Editorial policy · Method
Floor area under the Living Space Ordinance
Floor area
63.00 m²
| Of which sloped area at half | 3.00 m² |
| Of which balcony at a quarter | 2.00 m² |
How large a rented flat is in Germany is, in common practice, decided by the Living Space Ordinance (Wohnflächenverordnung, WoFlV), which applies to subsidised housing and is also used for private leases unless something else was agreed. Under its Section 4, floor areas of rooms with a clear height of at least two metres count in full, areas between one and two metres high count half, and areas below one metre not at all. Unheated conservatories count half; balconies, loggias, roof gardens and terraces usually a quarter, at most half. Cellars, storage rooms outside the flat, laundry rooms, lofts, boiler rooms and garages never count. For an attic flat with 52 m² at full height, 14 m² under the slope, 4 m² below one metre and an 8 m² balcony, that gives 61.00 m², not the 78 m² you get by measuring the floor. In Berlin's rent index, for a pre-war flat in an average location, that makes a difference of €98.31 of reference rent a month.
The rules of the Living Space Ordinance
The Living Space Ordinance decides in three steps what counts as floor area. First, which rooms: all rooms belonging exclusively to the flat, plus conservatories, balconies, loggias, roof gardens and terraces if they belong exclusively to it; not ancillary rooms such as the cellar, laundry room, loft or garage. Then, how to measure: by the clear dimensions between building elements, from the front edge of the finish. Finally, how much each area counts: in full, half, a quarter or not at all.
| Area | Counts as |
|---|---|
| rooms at least 2 m clear height | in full |
| parts 1 m to under 2 m clear height | half |
| parts under 1 m clear height | not at all |
| unheated conservatories, pools, enclosed rooms | half |
| balconies, loggias, roof gardens, terraces | usually 25 %, at most 50 % |
| cellar, laundry room, loft, boiler room, garage | not at all |
Worked example: an attic flat
A pre-war attic flat measures 70 m² at floor level, plus an 8 m² balcony. Of this, 52 m² have at least two metres of clear height, 14 m² lie under the slope between one and two metres, and 4 m² below one metre. Under the ordinance that gives 52 m² in full, 7.00 m² from the slope and 2.00 m² from the balcony, 61.00 m² in all. Simply adding floor and balcony gives 78 m², which is 17.00 m² too much.
| Calculation | Area | Reference rent per month |
|---|---|---|
| under the Living Space Ordinance | 61.00 m² | €517.89 |
| floor plus full balcony | 78 m² | €616.20 |
The two areas even fall into different size bands of the index (lines 70 and 72), and in euros the area decides anyway. For a new lease at €720, the rent-brake ceiling with the correct area would be €569.68. The small calculator above works out the area for your figures.
Where floor area matters
Reference rent. Rent indexes give euros per square metre; the reference rent in euros is that value times the area, and indexes also sort flats into size bands (Section 558(2) BGB names size as a feature). Rent brake and rent increases. Both limits are calculated from the value per square metre and the area. Modernisation. The cap of three or two euros per square metre depends on the area. Service charges. Without another agreement they are split by floor area (Section 556a(1) BGB), and part of the heating costs is split by area as well; the service charges page explains the split.
If the area in the lease is wrong
Many leases state an area without saying how it was worked out. Check it with a tape measure and floor plan using the rules above. If the actual area is clearly smaller, that affects the reference rent, the rent brake, every future increase and the split of service charges. Tell the landlord your measurement, ideally with a sketch and the measured dimensions, and ask to see how the lease area was calculated. At the next rent increase or service-charge statement the correct area should then be used. Whether and how far a discrepancy leads beyond that to a reduction or a refund is for the courts to decide in a dispute; a tenants' association can advise you.
What is often missed when measuring
- Included under Section 3 WoFlV are the areas under skirting boards, door and window frames, fixed stoves, heaters, cookers, bathtubs and shower trays, exposed pipes and built-in furniture. Measuring only the free floor gives too little.
- Excluded are chimneys, wall projections and free-standing pillars higher than 1.50 metres with more than 0.1 m² of floor area, stairs with more than three steps including landings, and door recesses.
- Window recesses only count if they reach the floor and are deeper than 0.13 metres.
- Heated conservatories count like normal rooms by their height; only unheated ones count half.
Measured or from the building plan
The ordinance allows both: measuring the finished flat or taking the area from a building drawing prepared for a planning procedure that shows the clear dimensions. If the flat was built differently from the drawing, the area must follow what was actually built. For old buildings with many alterations, measuring is therefore usually more reliable than any old plan. Measure each room separately, note length, width and the heights under slopes, and calculate the parts one by one, so every figure can be checked later, by the landlord too.