Is buying a house for a maximum of €350,000 realistic?

I will quickly calculate everything for you based on your values and the cost framework you provided.

Costs based on gross floor area:

The costs for a residential building of medium standard are approximately 1,150€ net / sqm gross floor area of the building according to our reference buildings. The value depends on the equipment and quality standard of the building. The given value is an average.

Determination of the gross floor area:

With a planned living area of 130 sqm, the gross floor area (depending on the building layout) will be approximately 1.2 to 1.3 times larger. For you, that means 156 sqm – 169 sqm. If we take the average here, we would have an area of 162.5 sqm. Since this area is probably not only on one floor, we would have an area per floor of 81.25 sqm. The same area would apply again for the basement. This results in a total gross floor area of 3*81.25 sqm = 243.75 sqm.

Calculation of construction costs:

The net construction costs are now calculated as follows:

Gross floor area * reference value = net construction costs:
243.75 * 1,150€ = 280,312.50€ – rounded to 280,000€

Additional construction ancillary costs such as specialist planners / architect / official fees... can be calculated at approx. 15%, so about 42,000€:

280,000€ + 42,000€ = 322,000€

Plus the VAT of 19% results in:

383,180.00€ gross total costs

Excluded from the costs are fittings such as furniture and furnishings. Also excluded are garden works. Included are the bathroom, the completed building with all coverings, and a certain proportion of terrace and paving works.

Please note that above I only calculated simply based on area. In addition to your quality and requirement profile as well as the basic layout of the building, the location of the building can also shift the price in both directions.