Would /that is incorrect/ be accepted for or is the same thing as /Det stämmer inte!/ If not, what does man say?
It's an accepted answer. You can also say det är inkorrekt (but that has a somewhat more narrow use in Swedish than in English) or simpler, det är fel 'that is wrong', or det är felaktigt (can be used about e.g. statements).
Also, please give a bit more info about "det är inkorrekt (but that has a somewhat more narrow use in Swedish than in English)". Thanking you in advance for your response.
It's very natural to respond to a statement with Det stämmer inte in Swedish. It's pretty neutral stylistically and runs less risk of sounding harsh than using any words that say something is 'false', 'untrue' or even 'not correct', since det stämmer inte also has the meaning 'that does not add up'.
I feel that in many cases it's a little more natural to use the word incorrect in English than in Swedish, where inkorrekt sounds (even) more formal and/or nerdy. But I don't think I can give any very clear rules.
Great information - I was especially interested in knowing about responding to statements.
Does "det stämmer inte" mean that something is morally incorrect, factually incorrect, or could it be used for both?
ahh after reading the question if "det stämmer" would mean "that is correct" I had a lightbulb moment. It is like german das stimmt. (maybe related to dutch overeenstemming (resamblance, agreement)