USA: Typically for us, about 7-ish hours, I have to go in the building before classes start before then though, making it about 8 hours. Sometimes, we have half days, but they’re pretty rare. We have all our classes, they’re just very condensed 4-5 hours.
Here, we start at like 07:00 (Mondays 08:10 or so) and we end at 14:50.
Norway: 6-7 hours apparently, from 08:00-14:00 (2: p.m.) or 15:00. (3 p.m.)
Italy: 5 to 6 h from age 6vro 19. For age 6-11 it’s common to have longer school days (8:00-16:00) to give parents opportunity to pick kids after work.
For age 11-13 it’s almost always from 8am to 13:00.
For age 14-19 depends on school, usually 30 to 36h per week, often on 5 days.