Merging plots: what two parcels together would allow
Developers in Vienna often buy the house next door as well. Azima reads the adjoining plots from the cadastre, adds up their areas and the existing buildings on them, and calculates the new building by building class — with the demolition of the neighbouring buildings in the calculation. In the browser, without an owner search.
A plot in a Gründerzeit block is often narrow and deep, and a new building rarely pays on it alone. Two side by side are a different calculation: one staircase instead of two, one facade, one courtyard. How large that calculation is can be read from open data — the plot areas in the register of the Federal Office of Metrology and Surveying, the existing buildings in the city’s roof model.
Calculate an address →What is computed — and where it stops
The calculation deliberately runs on the footprints of the buildings standing there, not on the plot area: a plot says nothing about building lines, courtyard and distances. Streets, railways, parks and cemeteries are not offered at all — their land use is in the plot register. Whether plots may be merged is for the land register and the development plan to say; the calculation says whether the question is worth asking.
Frequently asked
Will I find out who owns the neighbouring plot?
No. Azima reads the cadastre reference data without owners; anyone who wants to know who owns a plot applies for a land-register extract themselves.
Why not calculate on the plot area?
Because it is an area, not a building right. How much of it can be built on is set by building lines, courtyard and distance rules in the development plan. If you know the buildable area, you can enter it — then the new building is calculated on it.
Is my selection saved?
On the device, like the plan height and the buildable area. It never leaves the browser and is not an entry anywhere — below the calculation it says "chosen on this device".
What if a building spans two plots?
Then it counts entirely towards the plot on which its centre lies. In large blocks a plot can therefore look almost empty although the neighbouring building reaches across it — the note is below the list.
Can I pass it on as a spreadsheet?
Yes. "As CSV" writes areas, costs, revenues and every assumption into a file that Excel in Austria opens without an import dialogue — created on the device, without a server.
All measurements · For agents & developers · The light check
Basis: BEV cadastre reference data of 1 April 2026 without owners and the plot register (CC BY 4.0, land use under BANU-V), the City of Vienna LoD2.1 roof model and zoning (CC BY 4.0). Not legal advice, not an expert opinion.