Properly assessing house planning

Of course, you ultimately have to decide for yourselves what you want to afford, but I don't understand your calculation.

Originally planned were: (419,000 + 10,000 material for own contribution) * 1.05 (land purchase + notary). That then makes 3,220 euros/sqm, or 21,000 euros additional purchase costs.
If you say that you now save 15,000 euros in additional purchase costs, apparently 6,000 euros are omitted for the land, which then consequently costs 120,000 euros.
419,000 (140sqm * 3,000) + 120,000 + 6,000 = 545,000 euros or 3,900,-

Am I missing something, or have I misunderstood you somewhere?

Old project €419,000 + material costs about €15,000 (buffer) × 1.05 (incidental costs) = €455,700 = €3,532.59 New project €3,000 × 129 sqm = €387,000 + €52,750 (land) × 1.05 = €55,387.75 = €442,387.75 = €3,429... Grrrrr... calculated like this no big difference at first glance. What is eliminated is the labor effort in own work. To possibly also accommodate our wallet, it would be possible in this project to reduce the living area, ah I am getting a headache again :) In our region it is simply so difficult to get something, one possibly starts to fudge the numbers.

Believe me, I can totally understand that on a human level. I already get worked up when I’m allowed to buy a new monitor and mentally have the three 30" ones mounted on the wall faster than I could buy them via OneClick :D But here I have the advantage that it’s not about me and I can recommend the individual, reasonable 24" to others ;-)

Objectively considered, you have an offer on the table that ultimately costs you just as much as the one previously scrapped due to gut feeling. Even in the current project, no buffers have been considered and you lose 7% of living space. That somehow doesn’t make sense, does it?

I don’t know how prices are in your area, but if they’re always in that range, you better overcome the gut feeling or see what the second-hand market offers, where you can spread the costs a bit more and thus have less cost pressure.

Hello Sparstrumpf
Regarding your question, here are some figures from our current construction project: Fixed price from the construction company for a solid house with 146sqm living space without a basement according to Kfw 70 about €250,000 including garage. I calculate additional construction costs of €30,000, plus €10,000 as a sample buffer, €20,000 for the completion of the outdoor area, €25,000 for the kitchen, which makes a total of almost €335,000. We must not forget the plot of land at just under €100,000 (530sqm). That brings us to a total of €435,000, which is in the range of the project you described.
Our net income is about twice as high as yours, but I still do not want to finance more and therefore we are leaving Mainz.... In Mainz, a comparable property would easily be twice as expensive and then I would have the same ratio of net income to construction costs as you have in Neu Ulm.
From painful experience during a stay in the USA, I have drawn one conclusion: Never spend more than 30% of net income on housing (here loan installment + ancillary housing costs such as water, heating, electricity, telephone, taxes & insurance), otherwise serious problems are unavoidable!
The house should also be fully paid off no later than retirement, accordingly the repayment and the rate to be paid are calculated, which should then be below 30% of net income.

Best regards!
Marvinius2016

If you look at it very precisely, the original object was just under €3500 per sqm when you realistically include the self-performance (materials + time effort). This actually discouraged us from the whole topic.

You must not calculate like this if you ever want to come to a "green branch" in your calculation. Whenever prices per sqm are mentioned here or on the internet, it always refers to the house, including turnkey performance. "Turnkey" means - with a few exceptions - without painting work and floor coverings.

If you buy a pure developer measure - land and house from a single source - only additional costs for the notary and tax office remain; if necessary, painting and floor covering work must still be purchased. If you buy through a general contractor (purchase of land and house are two legal transactions), additional construction costs of around €40,000 always apply; without outdoor facilities and extras, in whatever form, and mostly with the knowledge that painting and floor covering work have to be carried out as self-performance or outsourced.

Rhenish greetings