New York is among five states that will add at least 300 hours of learning time to the calendar for some schools starting next year.
The three-year pilot program is intended to boost student achievement and make US schools more competitive on a global level. The other states participating are Colorado, Connecticut, Massachusetts and Tennessee.
Schools will work with parents and teachers to decide whether to make the school day longer, add more days or both.
Education officials say spending more time in the classroom will give students access to a better-rounded curriculum.