What is the Grundflächenzahl (GRZ)?
The Grundflächenzahl (GRZ) is Germany's site-coverage ratio: it states how many square metres of building footprint are permissible per square metre of plot area. A GRZ of 0.4 means up to 40 percent of a plot may be built over. Together with GFZ and BMZ it defines the permitted density of development. Mapular compiles GRZ reference values from all 16 federal states into one layer with a single, consistent schema.
How does the BauNVO define the Grundflächenzahl?
Legal status
Reference data
An authoritative input for analysis and screening. It carries no legal effect of its own.
The GRZ is one of the indicators of the Maß der baulichen Nutzung (the permitted intensity of development) defined in Sections 16 to 21a of the German Land Utilisation Ordinance (BauNVO). Section 19 BauNVO defines it as the permissible building footprint in square metres per square metre of plot area. Ancillary structures such as garages and driveways are counted under Section 19(4) and may exceed the value within defined limits. Binding GRZ values are set by municipalities in their development plans.
What this means for you
For you as a buyer this means GRZ reference values are ideal for screening, ranking and comparing sites at scale: which parcels allow a large footprint, where density headroom exists, which markets fit your product. For a concrete building application or transaction, always verify the figure against the legally binding local plan and, where needed, formal planning advice.
Which attributes does the GRZ layer contain?
- GRZ value: The site-coverage ratio recorded for the area, for example 0.4, expressed as permissible building footprint 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, so you can filter, compare and report by state.
- Classification: A harmonised classification of the record within Mapular's catalog schema, making values comparable across state boundaries.
The GRZ itself is defined federally in the BauNVO, so its meaning is the same everywhere. What differs is how the 16 states publish their planning data: formats, data models and level of detail vary considerably. Mapular normalises these differences into one schema, so a GRZ value reads identically from Flensburg to Munich.
What can you do with Grundflächenzahl data?
- Site potential screening: rank parcels and areas by permissible building footprint before you commission surveys, legal reviews or on-site visits.
- Density comparison: benchmark site-coverage levels across municipalities, districts and all 16 federal states to position products and prioritise acquisition markets with evidence.
- Feasibility pre-checks: run rough footprint and massing estimates on shortlisted sites early in the process, without reading a single development-plan PDF.
- Product enrichment: add a Germany-wide density indicator to valuation models, proptech platforms and internal GIS tools through one consistent data layer.
Where does the GRZ 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 GRZ layer cover?
The GRZ layer covers all 16 German federal states in one consistent schema, from the city-states of Berlin, Hamburg and Bremen to the large territorial states, so nationwide analyses need no per-state data wrangling.
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 GRZ 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 Grundflächenzahl
What does a Grundflächenzahl (GRZ) of 0.4 mean?
A GRZ of 0.4 means that up to 0.4 square metres of building footprint are permissible per square metre of plot area, or in other words that up to 40 percent of the plot may be built over. On a 1,000 m² plot, that corresponds to a maximum footprint of 400 m², before permissible exceedances for ancillary structures are considered.
What is the difference between GRZ and GFZ?
The Grundflächenzahl (GRZ) limits the building footprint relative to plot area, while the Geschossflächenzahl (GFZ) limits the total floor area across all full storeys. A site can have a low GRZ but a high GFZ: a slim, tall building. Both are density indicators defined in the German Land Utilisation Ordinance, in Section 19 and Section 20 BauNVO respectively.
Is Mapular's GRZ data legally binding?
No. Mapular's GRZ layer provides reference values compiled from official state publications and planning data. The legally binding figure 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 and comparison, and verify individual values before making binding decisions.
Which parts of Germany does the GRZ layer cover?
Mapular's GRZ layer covers all 16 German federal states in one consistent schema, city-states and territorial states alike. That makes it suitable for genuinely nationwide analyses, portfolio screenings and market comparisons without stitching together separate state datasets or reconciling different data models yourself.
Can a GRZ be exceeded?
Yes, within limits. Under Section 19(4) BauNVO, areas of garages, parking spaces, driveways and other ancillary structures count towards the GRZ, and the value may be exceeded for them up to defined caps. Development plans can also set their own deviating rules, so the binding details always come from the plan itself.
Where do the GRZ values in the layer come from?
The values are compiled from official state publications and planning data of the federal states and harmonised by Mapular into one consistent, Germany-wide layer. At source, formats and data models differ considerably from state to state. Mapular normalises geometry, attributes and classification so that values are directly comparable everywhere.