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.)
The school I work for runs eight 7 1/2 hours but we could run 7 flat if we had a bigger building or less students. We need three lunch periods to fit them all in the cafeterias.