Single-track YRE provides a balanced calendar for a more continuous period of instruction.  Students and all school personnel follow the same instructional and vacation schedule.  Single-track does not reduce class size, nor does it allow a school to accommodate more students.  The rescheduled vacation is placed throughout the school year into periods called "intersessions", allowing time for remediation and enrichment throughout the school year. 

Multi-track YRE is used primarily to alleviate overcrowding, although it also incorporates the educational values of single-track YRE, including intersessions. It was designed specifically for schools with a shortage of classroom space. Multi-track avoids double sessions and the extended school day. It also alleviates the need to build costly new buildings with their attendant operating costs. 

Multi-track divides students and teachers into groups, or tracks of approximately the same size. Each track is assigned its own schedule. Teachers and students assigned to a particular track follow the same schedule and are in school and on vacation at the same time. Multi-track creates a "school-within-a-school" concept. 

Example: implementing a four-track year-round calendar extends the capacity of a school by 33%. A school with the capacity of 750 students can accommodate 1,000 students, as only three tracks of 250 would be in school at the same time; there would always be one track on vacation or intersession every day of the school year.

Extended Year calendars lengthen the school year substantially, from the usual 180 or so days annually up to 240 days of instruction. 

Intersessions are the periods of time rescheduled from summer vacation and redistributed within the school year. They can be used as vacation but are usually utilized as instructional time for remediation and enrichment with both single and multi-track calendars. Intersessions typically involve school staff and community resources to provide a safety net and an academic boost to avoid failure or enhance achievement.