Rough cost estimate - 6 residential units 85m² Austria + 200m²

Hello everyone.

I did a bit of reading up.
Already able to gather quite a bit,... and formed a picture.
SORRY in advance for the dumb questions ;/

In short: I live in the [Winer Umland]. (Austria)
Got a farmhouse from my grandpa - and I’m now thinking about what I can do with it. Catchment area would be really good! Super beautiful area.
Financing I should be able to manage. (let's leave that aside!)

MY IDEA would be.
1. Renovate the 200m2 living space on 2 levels (each 100),... condition is okay,...
what can you roughly calculate per m2? => floor etc. needs to be removed. => should have underfloor heating.
2. Extension of 6 residential units of roughly 85m2 each => say 500m2 additionally
no basement - but on 2 levels (3 new residential units on the ground floor, 3 new residential units on the upper floor)

The plot belongs to "me".
Everything is connected and zoned as needed.

Want to make it nice. (upper middle class)
And rather ecological (solar power system, heat pump, etc.)

What can I ROUGHLY!! (rough helps me a lot) calculate per m2 for
1.1. having all external companies do it (renovation 200m2 + 500m2 new build)
1.2. doing it myself (I’m not clumsy or unwilling) (renovation 200m2 + 500m2 new build)

=> only then can/will I consider whether to bring in an architect at all. => because just planning and then not implementing would also cost some euros.

Looking forward to your input!
And sorry again for the "unnecessary" question => but it is kind of special after all.
(more area => lower price per area ... if that applies here too!)

THANKS!
Cheers from Austria!

I’ll put it this way: People you need for a project like this can spot a greenhorn at first glance. This can become a nice business that you, as the initiator, are involved in, but the others make the profit.

Approximately 1.2 million euros.

Roughly 1.2 million euros.

Yes, but in the sense of Deep Thought's answer "42". Renovate the farmhouse and install underfloor heating. Add six residential units. 1.2 million will already be a sporty estimate with Brauchstdunix calculation colleagues ;-)

1. To renovate his 200m2 living space on 2 levels (100 each),... Condition is okay,... what can you roughly estimate per m2? => floor etc. must be removed. => underfloor heating is to be installed.

150-350K?

2. Extension of 6 residential units of approximately 85m2 each => let's say 500m2 more no basement - but on 2 levels (3 new residential units on the ground floor, 3 new residential units on the upper floor)

I personally would not move into an apartment without basement usage. At least in the new multi-family houses here in our area, it is also very unusual to build without a basement, common areas, or other storage rooms.

Besides, your calculation doesn't add up. 85*6 is already 510. Then you have to add traffic areas and space for building services.

I alone see 1.2 million just for the 6 residential units.

And with 6 residential units, you don't want to do the work yourself...

Besides, your calculation doesn't add up. 85*6 is already 510. Added to that are traffic areas and space for building services.

Building services without a basement? - maybe that goes into the farmhouse next door / opposite (?) By the way, nowadays you no longer build six times the same size, not even 2x three equal sizes.