Are the ancillary construction costs calculated correctly?

Do I understand correctly. You keep half of the property (800 sqm) and want to build two bungalows on it (you and your brother), so each has about 400 sqm of space?

Yes, that's exactly how it is supposed to be. Why?

Sure, you don’t complete the purchase of the house before the notary. You only go there for the division or sale of the 1/2 share of the property (the buyer pays the sale) and for the mortgage registration. Then there are invoices from the land registry office.

That means my brother and I do not pay the notary but only the invoice for the land registry entry. How do I calculate the costs for the land registry entry?

Presumably, the land value will be used for this, so rather a fictitious amount. This then probably has to be stated – realistically.

However, it seems to me that you should still read quite a bit here in the forum, because with the roughly 250,000 EUR you are missing far more than just the mentioned – calculable – additional costs. Most of the time, you can only calculate this reliably if you are knowledgeable and know what extras still have to be paid to the respective provider.

Topic connections: I don’t think you will have any savings there just because a house is already connected. Rather, something will be added on top because before demolition the existing connections have to be deactivated. On the one hand, the connection costs are usually flat rates and on the other hand, the network operator also charges for the paperwork for the transfer etc. – and usually quite well.

That means my brother and I do not pay a notary but only the bill for the land register entry. How do I calculate the costs for the land register entry?

A notary fee still applies: after the land division, each must be assigned a plot and notary fees also arise for the certification/recording of the land charge. Has it already been agreed with the municipality that a bungalow may be built on the 400 sqm plots? Who pays for the demolition of the parental house?

The plot is about 1600 sqm in size

We will sell half of the plot to a planning / construction company.

I will split the other half with my brother, each of us will build our house with the said planning / construction company.

400 sqm! On the left and right, 3 meters each boundary distance, 5 meters in front, 6 meters at the back for a small terrace. That leaves 9 x 14 meters for the house. That is 126 sqm footprint, about 115 sqm living area. Provided that the building envelope does not throw a wrench in the works here. And what is the floor space index? I know: in the past, one did not exactly exhaust the entire or half of the floor space index with a single-family house, but that a bungalow should still fit on 400 now, and that without restrictive building boundaries, one can hardly believe. For how many people is a bungalow supposed to suffice each?

That was also my first thought. 400m2 for a bungalow is tight. You have a lot of land, so why do you want to squeeze your houses together like sardines?