The number of school days in a year depends on the state; 30 states have 180 school days, according to Education Commission of the States, 2013 update. Two states set minimum school days higher than 180 days, and 11 states have a minimum that falls between 160 and 179 days.
Eight states do not establish a minimum amount of required school days. These eight states instead measure hours of education. Even among the states that have the same number of required school days, how many hours constitutes a school day can vary. Students at higher grade levels generally have longer school days than students at lower grade levels.