What is the Geschossflächenzahl (GFZ)?
The Geschossflächenzahl (GFZ) is Germany's floor-area ratio: it states how many square metres of floor area, summed across all full storeys, are permissible per square metre of plot area. A GFZ of 1.2 allows 1,200 m² of floor area on a 1,000 m² plot. Because floor area drives lettable and sellable space, the GFZ is the key indicator for yield. Mapular compiles GFZ reference values from all 16 federal states into one consistent layer.
How does the BauNVO define the Geschossflächenzahl?
Legal status
Reference data
An authoritative input for analysis and screening. It carries no legal effect of its own.
The GFZ belongs to the indicators of the "Maß der baulichen Nutzung" defined in Sections 16 to 21a BauNVO. Section 20 BauNVO defines it as the permissible floor area per square metre of plot area, with floor area calculated from the external dimensions of the building across all full storeys ("Vollgeschosse"). What counts as a full storey is determined by state law, which the BauNVO explicitly references. Binding GFZ values are set by municipalities in their development plans.
What this means for you
For buyers, the GFZ is the fastest route from plot to potential: multiply plot area by GFZ and you have a first estimate of achievable floor area. That makes GFZ reference values ideal for yield screening and densification analysis. The binding figure for any specific project must always come from the legally binding local plan.
Which attributes does the GFZ layer contain?
- GFZ value: The floor-area ratio recorded for the area, for example 1.2, expressed as permissible floor area per square metre of plot area.
- Reference geometry: The polygon of the area or zone the value applies to, delivered in consistent geometry across all federal states.
- Federal state: The Bundesland the record belongs to. Relevant context, since the definition of a full storey follows state law.
- Classification: A harmonised classification of the record within Mapular's catalog schema, making values comparable across state boundaries.
The GFZ is defined federally, but Section 20 BauNVO ties it to full storeys under state law, and the definition of a Vollgeschoss differs between the 16 state building codes. Publication formats and data models also vary by state. Mapular harmonises the published values into one schema, and the state remains an attribute for context.
What can you do with Geschossflächenzahl data?
- Yield screening: estimate achievable floor area from plot size and GFZ to shortlist sites before commissioning architects, appraisers or legal reviews.
- Densification analysis: compare permitted floor-area density with the existing building stock to find under-used plots and redevelopment candidates across Germany.
- Market comparison: benchmark density levels across municipalities and all 16 federal states to steer acquisition strategy and product positioning with consistent data.
- Model input: feed a nationwide floor-area indicator into valuation models, feasibility tools and proptech platforms from one single consistent layer.
Where does the GFZ data come from?
Compiled from official state publications and planning data into one consistent layer: harmonised geometry, one schema, one delivery for all of Germany.
Which federal states does the GFZ layer cover?
The GFZ layer covers all 16 German federal states in one consistent schema, from dense city-state markets to rural regions, so floor-area potential can be compared nationwide without merging separate state datasets.
Coverage by federal state
- BBBrandenburgAvailable
- BEBerlinAvailable
- BWBaden-WürttembergAvailable
- BYBavariaAvailable
- HBBremenAvailable
- HEHesseAvailable
- HHHamburgAvailable
- MVMecklenburg-Western PomeraniaAvailable
- NILower SaxonyAvailable
- NWNorth Rhine-WestphaliaAvailable
- RPRhineland-PalatinateAvailable
- SHSchleswig-HolsteinAvailable
- SLSaarlandAvailable
- SNSaxonyAvailable
- STSaxony-AnhaltAvailable
- THThuringiaAvailable
Where the federal state publishes this layer, we carry it: 16 of 16 federal states today. Where it doesn't, we say so.
Coverage gap
Your region of interest isn't covered?
Coverage follows what each state and municipality has actually digitised, so there are real gaps, and they are not always where you would expect. Tell us the region and the layer you need and we will look into what can be sourced for it, including data we do not list today.
Tell us what you needHow do you get access to the GFZ layer?
One unified dataset: Ready for direct integration into your GIS, CAD, or BI tools. Standard formats, documented schema.
Mapular Explorer: Instant planning interface, no GIS setup required. Filter, analyse, and export from your browser.
Frequently asked questions about the Geschossflächenzahl
What does a Geschossflächenzahl (GFZ) of 1.2 mean?
A GFZ of 1.2 means that up to 1.2 square metres of floor area are permissible per square metre of plot area, summed across all full storeys. On a 1,000 m² plot, that allows up to 1,200 m² of floor area: a first, fast order of magnitude for how much building a site can carry.
How is the Geschossflächenzahl (GFZ) calculated?
The GFZ is the ratio of floor area to plot area. Under Section 20 BauNVO, the floor area is calculated from the external dimensions of the building across all full storeys. What qualifies as a full storey ("Vollgeschoss") is defined by the law of the respective federal state, so identical buildings can be assessed differently across state lines.
What is the difference between GFZ and GRZ?
The Geschossflächenzahl (GFZ) limits total floor area across all full storeys relative to plot area; the Grundflächenzahl (GRZ) limits only the building footprint. A high GFZ with a low GRZ describes tall, slim development; similar values describe flat, spread-out development. Both are federal density indicators from the BauNVO, Sections 20 and 19.
Is Mapular's GFZ data legally binding?
No. Mapular's GFZ layer provides reference values compiled from official state publications and planning data. The legally binding value for a specific plot is set in the municipal development plan or follows from the planning-law situation on site. Use the layer for screening, comparison and pre-checks, and verify individual figures before binding decisions.
Which federal states does the GFZ layer cover?
Mapular's GFZ layer covers all 16 German federal states in one consistent schema. City-states and territorial states are included alike, so nationwide portfolio screenings, market comparisons and densification analyses work without assembling and reconciling separate state datasets first.
Why does the GFZ matter for yield estimates?
Floor area is the closest planning-law proxy for lettable and sellable space. Multiplying plot area by the GFZ gives a first estimate of achievable floor area, and thus of revenue potential, before any design work. That makes GFZ reference values the natural starting point for site shortlists, feasibility pre-checks and portfolio comparisons.