Online static tools for concrete, wood, steel

Does anyone know of a tool like this for home use, especially for concrete or masonry?

For wood and steel, I know this Eurocode tool. I would just like to compare whether, for example, a 12x12 concrete post with reinforcement has the same load-bearing capacity as a corresponding 12x12 wooden post.

I can help: No, they do not have the same "Stützkraft" (and what do you mean by "Stützkraft" in your context?)

There are material characteristic values and these are fundamentally different. Compressive strength and buckling stiffness are too different here.
Furthermore, you need software that is rather professional for further (targeted) calculations and as far as I know, it is rather expensive (5K). And: that is why there is the profession of a structural engineer who certifies with his signature that what he has calculated will hold. Structural analysis was in my opinion one of the most difficult subjects in civil engineering studies. But I could be wrong and there might be some freeware available. However, you still need to know how to handle it.

A lot of text, but in the end I advise you simply not to carry out life-threatening calculations yourself.

I meant with the comparability whether I could use a 12*12 concrete post/concrete pillar instead of a 12*12 wooden post for the carport roof, for example. Or alternatively build appropriate columns with shuttering blocks on which the roof beams then rest.

A carport roof will be approximately 3x5 - 4x6m in size, which is life-threatening if it collapses! Do not underestimate wind and snow loads. The weight of a 12x12 beam from a height of 3m alone can easily crush an adult. Children even more so. A basic understanding of statics should be present. Posts alone are not enough; for stable support, you must either fully clad the sides to create a shear effect or brace a cross between the posts (e.g., diagonal braces). Do you know Ivar from Ikea? They had a cross brace at the back so the shelf wouldn't tip sideways. The same thing can definitely happen with poorly built carports. With you, sorry, the understanding seems to be lacking, so I don’t give building tips except maybe "take a kit," which is type-approved.

To answer your question: Concrete can bear much higher support loads than wood. 12*12 is already oversized for wood. There are tables for the calculation.

The specification with the 12 cm wooden post comes from a carport kit that would be suitable for our snow load zone, but I can't use it because the dimensions are not optimal. And I don't want to tinker and patch up the kit either. Therefore, I wanted to basically rebuild the thing on this basis, but with slightly modified measurements.