How much does a mostly self-built house cost?

Hello, we are planning a small single-family house. My husband is a carpenter and wants to do everything himself. That means timber frame walls and the roof are no problem at all, electricity neither, a friend will do that. We can also plaster, do painting work, and lay floors ourselves. We would only need outside help with heating and sanitation, the basement, possibly windows/doors/stairs. I find it difficult to estimate the costs. How much will it cost us, or how much do we save through all the work we do ourselves? (Does anyone, for example, know what is budgeted for the individual trades)? The house will be max. 10x10 m in size, 1.5 stories. Does it make much difference in cost if we build, for example, only 9x10 or 9x9 m? And what does a basement cost?

First of all, it takes 2+ years of time to do the mentioned things alongside the job itself, and of course the warranty :/

Of course, there are also helpers and a site manager. We already assume that it will take us longer because of that....

The question is still very general. In the end, you can only save part of the labor cost; because friends/helpers also cost a little (at least food, if they do more maybe something additional?). You also have to procure materials. Other incidental costs etc. remain just as high. Otherwise, you cannot make any cost estimate based solely on the basic dimensions. There are way too many parameters! - Wall thicknesses / insulation concept (which energy level should be achieved, from the Energy Saving Ordinance minimum up to passive house, there are big differences) - Equipment in every respect (just a few examples: no roller shutters - electric smart home-capable roller shutters; 2 sockets per room or more, WLAN or network cabling; pit toilet or Japanese popo massage wellness toilet etc., wood tiled stove or geothermal heat pump...) - and so on - and so forth. For the basement/foundation, it also depends heavily on the soil (which type of basement wall/waterproofing is needed, for example). I always read something here in the forum in the direction of 60,000+ (with some "interior finishing" like doors, heating).

...and is making the calculation without helpers....because they also have their own job to earn their bread. And a house at the expense of my friends' free time is immoral

I find it difficult to estimate the costs.

Hello, you also have trouble using a forum
What does a car cost, Dacia or RR?
So maybe with your question go into detail, that’s my advice to you.
The costs of building a house vary by region. I see from your profile that you live in BW and you are male... Your husband is a carpenter, so he is a professional and should roughly know the costs of a house?!

Furthermore, we have a forum filled with cost estimates, house costs, etc. Just take a look

What does it cost us, or rather what do we save through all the own work?

We don’t know where the own work should start.

Best is for you to consult an architect, you need one anyway for the designs and documents. He can create a cost breakdown and subtract your own work.
However, you should know beforehand that the time you spend on the house build longer also has to be paid, namely through double burden of loan and rent, double burden of own labor, as well as tools, disputes... possibly even the relationship or friendships – friends are not fill-ins without free time who always have time when you expect it...