Single-family house construction cost calculation - does it fit?

It's obvious that a building finance advisor will always try to convince you to plan more with EUR 3,000/m².
The wedding planner also feeds you a lot of nonsense because they want to make money, with the motto "You only get married once, so surely you don't want bare chairs, etc."

But well, if you really can't do much yourself, have to let everything be done, and presumably consider parquet, walls in Q4, the EUR 50/m² tile, Villeroy & Boch ceramics, Grohe fixtures, 4 network sockets per room, etc. as "standard"... then you'll end up at EUR 3,000/m².

Complete garden including fence, driveway, lawn, trees available here by the way at a friendly price of EUR 50,000.

So no. If you want all that, your budget is not enough. But maybe you'd rather live in your own house and walk on laminate like a Hartz IV recipient instead of in a rental apartment?
At least that's how it is for me and I am debt-free in 25 years.

Honestly, I have 4 offers on the table. 145 sqm2, without a basement. If I negotiate a little more, I can get below EUR 480,000... Plus about EUR 60,000 additional construction costs! So EUR 460,000 including additional construction costs is completely unrealistic for 175 sqm2! Even with 50 percent own contribution, you won't manage with those costs!

Honestly, I have 4 offers on the table. 145 sqm2, without a basement. If I negotiate a little more, I'll get under 480,000 euros... Plus another approx. 60,000 ancillary construction costs! So 460,000 including ancillary costs is completely unrealistic for 175 sqm2! Even with 50 percent own contribution, you won't manage the costs!

160 sqm, not turnkey, but the rough work is done.

With a few extras, we’re at 375,000€, leaving 85k for the rest. If the plot has no major peculiarities, that should be doable.

160 sqm, not turnkey, but the roughest part is done.

But a lot more is still added: - special requests - all floor coverings - all interior doors - interior window sills - complete house plastering and sanding - all painting work - normal incidental construction costs - possibly garage or carport - all exterior facilities including terrace and driveway

I think 3000 - 3200 € per sqm + the already mentioned additional costs are quite realistic. But the additional costs should not be underestimated. They can really add up.

Since the plot is already available, you can start with the planning. That only costs time, not money. Lots of reading, finding nice floor plans from the internet and drawing them yourself to scale on paper or with a program. Once you have the first good approaches, you can visit house providers and get some offers.

Friends of mine have also received good offers from regional solid house providers. They are sometimes a bit blunt and not the born salespeople, but they can still build good houses.

But you must definitely deal intensively with the offers. And understand every point. Research, notes, etc. are very important. I believe that most people do not really understand the offer and compare apples to oranges. A difference of 20-30k in costs between providers can arise very quickly.

But there's quite a bit more: - special requests - all floor coverings - all interior doors - interior window sills - complete house puttying and sanding - all painting work - normal incidental construction costs - possibly garage or carport - all outdoor facilities including terrace and driveway

Except for interior doors and window sills, that comes with every turnkey house. And all of that can be done well as own work.

Except for interior doors and window sills, this is included with every turnkey house. And all of that can be done well as DIY.

Sand and fill the whole house? But yes, the rest also has to be done for a turnkey house and costs a lot of money if you have it done. And doing a lot yourself was not feasible for the OP.