this "price per SQM" is absolute nonsense. this is important for commercial buildings; in the private sector, it is NOT a measurement. 1. the price per SQM can hardly be generalized. it always depends on the standard; many other factors play a role. (100sqm quite angled and with bay windows, etc., are quickly more expensive than 150sqm as a square house!) 2. the additional costs cannot always be calculated flat-rate. outdoor facilities can vary by up to 100% even with identical requirements. there are plenty of "traps" that always have to be considered individually according to the building plot 3. who actually cares about the price per SQM? no one. in the end, what matters is how much MY house according to my wishes will cost and whether I can afford it. regarding 3.: self-performed work is often calculated optimistically. you always have to consider time, material usage, and your own skills. i am usually slower than the professional, don’t work quite as well, and have more material waste. what exactly do i want? only when this is clear do i have even an idea of what one "SQM" will cost purely from a calculation point of view. the cost drivers are usually somewhere else. how complex is my planning? what standard, whether energetically or in terms of equipment, do i want? what exactly will still come in detail? (foundation/civil engineering, outdoor facilities, container etc.) as a cautionary example: we had a fixed price of 295k euros for the house. (turnkey, wall, ceiling, and floor (except the bathrooms) self-performed work) our builder went bankrupt. but we were confident, after all we only paid retrospectively and thus never overpaid the builder. then came the big blow: finishing the build was not feasible with the builder’s calculated budget at all. he would have gone bankrupt at the latest with our construction! it doesn’t help. we did everything right and never paid upfront... and still ended up in trouble. in the end, instead of 295k including garage, we had to pay 350k EXcluding garage. thankfully, i kept it modest and built the house "one size smaller than mathematically possible." if i hadn’t done that: personal bankruptcy and case closed. again as a warning: my misfortune, which was not my own fault, i followed all the "instructions" correctly, now costs me a lean 500 euros more monthly than originally calculated. if i couldn’t have paid that, i would have, frankly speaking, been screwed: personal bankruptcy. anyone who plans their house construction with theoretical prices per "SQM" is basically doomed to fail. it simply doesn’t work. if you can just absorb 20 or 30 grand more or less, then it works as a rough guideline. anyone who can’t: FORGET IT. realistically calculate what is possible, take on a maximum of 80% of that, and then don’t get into trouble. a new build will usually, i have talked to countless neighbors, ALWAYS be more expensive than you think. that is seriously just not plannable down to the last euro.