1 to 3 days - norovirus hits fast and leaves fast, per the CDC.
Two caveats do the real work: you can still spread it for a few days after feeling fine (strict handwashing, no cooking for others yet), and the actual danger is dehydration - much-less-frequent urination, dry mouth, dizziness, or listlessness mean medical care. It is a virus; fluids and time are the treatment.
What to do
Common questions
How long does norovirus last?
One to three brutal days. Per the CDC, most people with norovirus get better within 1 to 3 days - the illness hits suddenly with vomiting and diarrhea and leaves nearly as fast. Two caveats do the real work in this answer. First, contagiousness outlasts symptoms: you can still spread the virus for a few days after you feel fine, which is why the return-to-work and return-to-cooking question deserves a cautious answer - strict handwashing and no food prep for others for at least a couple of days after symptoms end. Second, the danger is not the virus but the dehydration, especially in small children and older adults: the warning signs are urinating much less than usual, dry mouth, dizziness, and listlessness, and those mean medical care, plus small frequent sips of fluids or oral rehydration solution in the meantime. Antibiotics do nothing - it is a virus - and there is no specific treatment, just fluids and time. Pymander, a free AI doctor available 24/7 by text, can help you manage the course safely.