Construction costs single-family house estimate by sqm or volume

Different offers with almost identical prices suggest that they are plausible.

... and/or to the same extent hide (additional) cost items, disguise them as "based on effort," or assume them as "provided by the builder."

An acquaintance mentioned the following reference values:
sqm = €2100 (gross)
cbm = €490 (gross)
our best offer is at:
sqm = €2500 (all costs including additional construction costs calculated)
cbm = €580 (all costs including additional construction costs calculated)

So the question is whether the additional construction costs amount to €400/90 per square/cubic meter here, because only then would the apple value and the pear value be appropriate ;-)

Realistic prices can be found in the form of offers from young property developers – there is a bit of profit included, but it doesn’t hurt to translate that into a buffer in the calculation.

Thank you very much for the numerous responses.
My gut feeling tells me that there is still room for negotiation. However, your answers take the wind out of my sails.

Regarding the ancillary construction costs that are "hidden": I find that unfair. At such prices and "surcharges," fairness would be appropriate.

For the client-side costs: don't the surveying and soil investigation reports provide enough information to calculate ancillary construction costs and construction costs more accurately?

Somehow, when you think of additional construction costs, you apparently only think of earthworks.

Have a look:

https://www.hausbau-forum.de/threads/liste-der-anfallenden-baunebenkosten-bauseits-teurer.9737/

Hello Basti,

I’m also from the Reutlingen district, but I just built on the Alb or on the edge of the Alb near Reutlingen (also without a basement and without a garage). You can certainly calculate with €2,500 / sqm (excluding additional construction costs) for a turnkey house here. With some own contribution, we were at about €2,100 / sqm, but our construction contract dated from 2019. Since then, prices have gone up significantly. It’s important that you also think on top of that about all additional costs. The corresponding link has already been posted.

May I ask where in Reutlingen you are building? In the city or somewhere “off” in the district? In our area on the Alb, for example, the ground mainly consists of stones.

Regards from the Swabian Alb!

Regarding the additional construction costs that are "hidden": I find that unfair.

Additional construction costs are not hidden; they must be paid by the builder. That means: you have to take care of the prices. Some general contractors include them in their calculation. And yes, earthworks up to 30cm are usually included in the offer. What goes beyond that is your responsibility, your invoice, your concern. Everything that concerns the property. The general contractor builds the house on your property, the property is yours, the costs are yours.