How do I determine the house costs before buying land?

Hello,
I (f, 27 years old) am new here and my boyfriend (28 years old) and I are just at the very beginning of our dream of owning a home. In our town, building plots will be sold in the next few months. We would very much like to purchase a plot there. We plan to start the house planning in 2022 and begin construction in 2023.

Does anyone here have any idea how we should proceed?

I would like to know the cost of the desired house before buying the plot. My boyfriend is a bit more relaxed about it since prices will change by then. Would you have the house costs calculated before buying the plot? If so, where?

We have already looked through many prefab house catalogs and have a rough idea of what the house could cost. But so far, all prices are from our own research.
We are estimating house costs of around €300,000-350,000 for a 150 sqm city villa with a garage. Also, we want rather modern technology (heat pump, electric shutters, underfloor heating, etc.). The building location is in NRW.

What do you think?

We would start the house planning in 2022 and begin construction in 2023.

That’s still four years until actual costs occur. What do you want to calculate today?
- Will you still be together in four years?
- House planning for two or will there already be children by then?
- Financial situation?
- Do you know the legal requirements for 2023 (e.g. Energy Saving Ordinance)?
- Do you know the development of construction costs until 2023?
...

Clear answer to your question: You cannot even remotely calculate the costs for 2023 today.

What you can certainly do is make a rough calculation as of today. Take €2,000-2,200 (you want a rather better equipment) x sqm + garage/outdoor facilities/kitchen etc.
To be safe, just add 25% on top and hope that you can cover the price increases of the coming years with it.
===> the house you mentioned you will in my opinion not get for €300,000 in 2023, €350,000 should be the lower limit. Personally, I bet on a 4 at the front.

I would first secure the plot of land. The development plan (usually always available in new development areas) then specifies quite a bit. "City villa" is currently trendy and therefore usually not a problem. Your ideas (garage, electric shutters, etc.) probably won't fit the budget. Expect around €2000-2500 excluding incidental construction costs, garage, outdoor facilities... It probably won't get cheaper in the next few years. Especially not the plots of land.

Nordanney was faster

Thank you for your opinion, my friend says roughly the same. I guess I have to admit defeat...

I am a bit surprised about your price estimate per sqm/living space.

On Immoscout, for example, you can find the following table:

Gebäudekosten für Wohnhäuser in EUR/m² Wohnfläche

Ausstattung	einfach	mittel	hochwertig
Ein- und Zweifamilienhaus	1,100 EUR	1,350 EUR	1,800 EUR

I understand that prices will increase over the years and one can only speculate. But are the tables on the internet really that outdated?