Single-family house: Is the rate realistic? How much house can we afford?

Yes, it is currently an unfavorable time to build. We first bought an old building and after paying it off, built new. In both cases, the 1/3 rule regarding the bank installment worked out. Thanks to a salary increase for my wife, the bank installment and additional costs are currently under 1/3 of our net income. That is quite comfortable and also leaves some leeway for the announced increases in energy costs.... Maybe you just have to face the facts that you currently have to expect a monthly installment of €3000 for a new build and should stay away from it if you have less than €9000 net per month.

As I understand you, you therefore assume that any new build - regardless of size, how it is built, and how much personal work is put in - costs at least €1.1 million and that one should stay away from it if one does not earn at least €108,000 net per year (= €180,000 gross), no matter how much equity is brought in and even if one already has developed building land in the village? I am really cautious, plan with a big buffer, and like to be a pessimist in such matters. But I consider that exaggerated.

Oh, no additional note: If I only consider our monthly net salary and take one third of it, I end up at €2,100. Not even according to the very simple and rough rule of thumb would I be very far from the €2,500 ... :)

The conclusion: Even if we wouldn't live one bit differently than we do at the moment, we could already afford a maximum installment of €2,200. In 2024 even €2,500

You just have to keep in mind that the installment then has to be paid for many, many years, not just a few months. I would take your absolute "pain threshold", minus 10%. Then calculate with that and see what you get for it before you turn 80. ;)

You just have to keep in mind that the rate has to be paid off for many, many years, not just a few months.

I would take your absolute "pain threshold," minus 10%. Then calculate with that and see what you get for it before you turn 80. ;)

As I said, I will get salary increases of about €100-150 every year, about €300-350 every two years. That means that by 2030 I will already have over €1,000 net more per month available than at the start of the construction. Even with children, inflation, etc., I therefore assume that paying the rate will be easier rather than more difficult.

On the other hand, I didn’t want to pay off until 80. I was more thinking of 30 years, then we would at least be in our mid-60s...

Just for fun, if I assume the absolute pain threshold minus 10% and "pay off until 80," we can pull out €1.5 million. I still wanted to stay somewhat realistic somewhere... :)

Yes, it is currently an unfavorable time to build. We had first bought an old building and after it was paid off, built a new one. In both cases, the 1/3 rule regarding the bank rate worked out. Thanks to a salary increase for my wife, the bank rate and incidental costs are now under 1/3 of our net5 income. That is quite comfortable and also leaves some room for the announced increases in energy costs....
Maybe you just have to face the fact that for a new build you currently have to expect a monthly rate of 3000€ and should stay away from it if you have less than 9000€ net per month.

Unfortunately, you are comparing apples to oranges. For existing properties, the situation is currently absolutely not better than for new builds, rather the opposite. The interest rates are the same, plus you sink even more money into the additional purchase costs. If you add the costs of a proper renovation on top, existing houses are currently way too expensive.
I have already hinted at the topic of renting, but to make it even clearer... in Germany, we are talking about an average household net income of just over 3600€, so according to your rule, 1200€ for housing. Good luck finding an apartment for a family with 1-2 children in large parts of the country that stays below last year’s incidental costs and is reasonably nice. A rule that can only be fulfilled if you have favorable conditions (above-average income, cheap housing) is completely useless. Maybe the rule worked 10 years ago. For several years now, it usually no longer works unless you happen to have an old rental contract.

I didn’t want to pay off until 80, though. I was rather thinking of 30 years, then we would at least already be in our mid-60s...

A good goal is 20-25 years. If you are significantly over that, you have little reserves if it gets more expensive or the interest rates rise for the follow-up financing.

we are talking in Germany about an average household net income of just over €3600 […]

And not even that shows the magnitude - in my opinion, the much more meaningful median value is significantly lower.

According to the rule propagated here, we would now be at the limit. With 2 decent salaries, DINKs. And for €380k property in a good location from the parents, so 6.5% saved. (of course, this is currently due to the interest rates)

If it’s tight for us according to the rule, families with children would be ******.