Construction costs per square meter - how to calculate?

I am bidding: 1650€/sqm despite the freaking expensive ventilation system and roof design… plus almost exactly 20,000€ ancillary building costs. And you can see: one calculates without, the other with earthworks/ancillary building costs.

Comparison is pointless. Even the ancillary building costs can triple if you have bad soil conditions. If someone then adds that to the house costs, it is practically a total falsification.

At a "cheap" 3000€ per square meter, that's already a difference of many thousands, depending on what you calculate with

It is also just one factor that you even get a ballpark figure. 3000€/sqm (house construction 2022, 2023, currently 2024) reflects the living space of a simple standard house: plastered, Renewable Energy Act minimum requirements, no exclusive frills, no exotic building materials.

I have the feeling that I/we already wrote this to you….
It says:

3000€/sqm is a guideline for a standard house, square, practical, good, plastered. Standard bathroom, no high-end luxury bathroom. Plastic front door, no wood, no aluminum.
It is cheaper to build in the north, more expensive in the south. If you want to use higher-quality materials or improve the KfW standard with photovoltaic, something like that comes on top.

… that’s what makes building a house expensive: the extras.

I keep wondering when this nonsense with "what does the sqm cost??" will finally stop. Apples are regularly compared to oranges. Let's take the North German as an example: there the 84 sqm bungalow costs 2,200 euros per sqm. The 150 sqm 1.5-story costs 1,500 euros per sqm. Conclusion: smaller houses are more expensive than larger ones. Bungalow is more expensive than 1.5-story, for whatever reason. Then I haven't even thought about regional prices yet.

Let's take the North German as an example: there, the 84 sqm bungalow costs 2,200 euros per sqm. The 150 sqm 1.5-story house costs 1,500 euros per sqm.

Who offers such prices? Even the bargain basement Town & Country charges from 2,700€/sqm for its small 77 sqm bungalow in the north and roughly from 2,000€/sqm for the approximately 145 sqm Flair 148 - in the simplest standard (both in terms of features and energetics). And these are never the prices for turnkey, as at least the painting work + flooring are missing (not to mention any special requests).

Therefore, one thing is clear, it is not enough to simply say "I paid 2600 euros/sqm."

At least the year of construction, the total living area, and the region must be included. Ideally, a brief list of the key points and special features of your own planning.

And, in general, it only applies that with such values you get a first rough estimate and overview price.

Thank you very much for your answers. I am currently really very unsettled because of the high construction costs in general. Then the prices for a "mid-range" finish also seem to vary greatly. Depending on what you consider to be "mid-range," where you live, etc., you read about €2500/sqm or €3000/sqm or more like €3500/sqm. But in total, that makes a huge difference in the end. A friend is currently having a new bathroom installed and has cost estimates from 4 companies ranging between €18,000 and €32,000! For the same bathroom. Something must be wrong there, right? I am really afraid of being taken advantage of and therefore try to inform myself as well as possible in advance about prices and services.

In addition, we only want to do a basic renovation and an extension. Finding prices for that is even harder. Next week I will visit the house with an architect who is also an energy consultant. She will advise us on energy matters and provide a cost estimate for the project. I am very curious about that. At the same time, I already know that I can hardly assess the cost estimate. Time and again you hear about estimates made beforehand that turned out to be far too low. Then the builders had to pay a lot extra. Or the estimate is very high. But now I wouldn’t know whether that is simply due to a lack of price awareness or if someone just wants to line their pockets. In any case, I plan to visit a renowned carpentry firm from the region here to also get a cost estimate. Maybe someone also has experience with realizing a renovation and extension project with a carpentry firm? The carpentry definitely offers additional floors and extensions and seems to have a lot of experience/is well-known. Very large family business, established here for 50 years.