A small powder room.
The question is extremely vague.
It really depends on the extent of the work. I would say the average powder room remodel takes about 3-5 days with one carpenter and one helper.
Three days would include a new floor, toilet, and vanity. I would say 5-7 days if you are also painting and replacing/adding things like exhaust fans, light fixtures, and trim work.
I would say that an average remodel of a basic powder room would take 3 days. The basic remodel would consist of removal of the existing fixtures and trim, then fresh paint. Followed by the flooring installation, these steps should be able to be completed in a day or two at most. Next would be the installation of the new trim, toilet, sink and hardware like towel bars/loops tp holder light fixtures etc.
To remodel a powder room its all depend on the material you using are you using a pre-made vanity with counter top or it is custom counter top, between cabinets, tile, granite, electrical, and paint i would say it need about 5-10 days.