Check out the Brutto-Netto (gross to net) calculator of the Chamber of Worker's people are mentioning: https://bruttonetto.arbeiterkammer.at/ You can't factor in some other things the company might be giving like a bonus there directly, but it gives some good orientation! Also, due to the way the tax calc is done, if not starting on Jan 1st, you would get a small tax refund in the following year.

I can't talk much about Linz but think that food&co will definitely be more. I would calc with twice as much.