- More than 10 per cent too small = defect. The Federal Court of Justice (BGH) draws the line at 10 per cent; above it, you reduce the rent by the full shortfall.
- Three years back: You can reclaim overpaid rent for the last three years.
- Service charges by actual area, with no 10 per cent tolerance: every square metre too many costs you money in the statement.
- Rent increases too: The comparable rent applies per actual square metre, not per square metre in the lease.
Paying too much rent?
See in two minutes whether your rent is above the legal limit. Free, no risk.
What does the 10 per cent rule say?
If the lease states a floor area, you are entitled to that area. If the flat is smaller, that is a defect (§ 536 BGB, German Civil Code). The Federal Court of Justice treats it as material once the shortfall exceeds 10 per cent; the rent then drops by the percentage of the shortfall, and the only thing you have to prove is the area.
Example: The lease says 80 square metres, you measure 70. That is 12.5 per cent less.
On a net cold rent of 1,000 euros you pay 875 euros. For the last three years you reclaim 36 months times 125 euros, so 4,500 euros.
Below 10 per cent there is no reduction, not even pro rata; the threshold is meant to stop disputes over trifles. If the lease puts "approx." before the figure, nothing changes: the 10 per cent threshold still applies.
How do you measure correctly?
What counts is what the parties agreed; if there is no agreement, the Wohnflächenverordnung (German Living Space Ordinance) applies. Under it, areas count differently:
Measure every room along the inside of the walls, and include alcoves and bay windows from 1.50 metres wide. A laser distance meter is enough; in a court dispute, a court-appointed expert decides.
What applies to service charges?
If operating costs are allocated by square metre, the actual area always counts, even if the shortfall is under 10 per cent. The Federal Court of Justice has scrapped the tolerance here, because otherwise one tenant pays for area that another tenant in the building uses.
So check every statement for the area applied. If it is too large, object within twelve months of receiving the statement and reclaim the difference; how to do that is explained under Objecting to the service charge statement.
What applies to a rent increase?
A rent increase up to the local comparable rent is calculated as a price per square metre. Here too, the actual area counts, with no 10 per cent tolerance. With 70 actual square metres instead of 80 in the lease, the landlord may only demand 70 times the comparable price; an increase letter that calculates with 80 asks for too much.
Measure before you agree to anything
If you agree to an increase based on the wrong area, you pay it. Check the area before you sign, and object if it is wrong. How much is permitted is explained under Permissible rent increase.
What to do
- 1. Measure: every room under the Living Space Ordinance, with a sketch and dimensions.
- 2. Work out the shortfall: area in the lease minus actual area, divided by the area in the lease.
- 3. Write to the landlord: the area, the shortfall, the reduced rent from next month and the refund claim for the last three years.
- 4. Recalculate service charges and increases: every statement from the last three years with the actual area.
If the landlord disputes your measurement, a survey by an expert is worth it; in the end, whoever is in the wrong bears the cost.
Frequently asked questions about flat size
The lease says "approx. 80 m²". Does the 10 per cent rule still apply?
Yes. An "approx." covers small deviations, no more than the 10 per cent that applies anyway.
The flat is 8 per cent smaller. Do I get anything back?
Not on the rent. On service charges and rent increases, yes: there the actual area always counts.
How far back can I claim?
Three years, counted from the end of the year in which you paid (§§ 195, 199 BGB). Claims for older payments are time-barred.
Does the balcony count as living space?
Under the Living Space Ordinance usually a quarter, at most half, unless the lease says otherwise.
Is your rent above the limit?
CONNY checks for free whether rent control applies to your flat and enforces the reduction. You only pay if we succeed.