The “Teaching and Learning International Survey” (TALIS) asked lower secondary school teachers around the world how they spend their work time. American teachers report working 45 hours a week during the school year. Teachers in other countries report an average 38 hour work week. (Do note that self-reports of work hours aren’t always terribly accurate. Also, the American number is a bit higher than other sources show. But even if the measurements are imperfect, there’s no reason to think that any biases are different in the U.S. and elsewhere.)
Interestingly, the 7 hour difference in work hours is entirely in the time spent actually teaching. There’s not much difference in the time spent on other tasks. Teachers in the U.S. spend more time teaching than do teachers elsewhere. Here’s a little chart of how the American teachers spend their time.
Perhaps not surprisingly, after actually teaching, time is spent mostly grading and planning.
The numbers for teachers outside the U.S. look pretty much the same, except for fewer hours teaching and a bit less in the catch-all “all other” category.