Schools operating on a year-round calendar forgo a long summer vacation and hold classes throughout the year. Year-round schools do not typically hold more instructional days than those operating on a traditional calendar (those that do are known as extended-year schools). Instead, they rotate between blocks of contiguous instructional weeks and short vacations. The primary goals of year-round schooling are to mitigate learning losses that occur during the summer months and to maximize the use of instructional facilities by holding classes throughout the year.

Internationally, year-round schools are most common in the United States. Within the United States, year-round schools are not common. Of the 3,000 schools employing a year-round calendar, most are located in the western states and are almost exclusively public schools. Most year-round ...