Funding and staffing
Student-teacher ratio vs. class size
Learn why a California school's student-teacher ratio can differ from the number of students in your child's classroom.
4 min read
A school with 600 students and 30 teachers has a student-teacher ratio of 20 to 1. The ratio describes staffing across the whole school. Class size counts the students in one classroom or course.
How the ratio is calculated
The calculation divides total enrollment by the number of full-time-equivalent teachers. A full-time teacher counts as 1.0. A half-time teacher counts as 0.5.
The teacher total may include special education teachers, reading specialists, intervention teachers, and other educators who work with smaller groups. Those positions count toward the schoolwide ratio even when they do not lead a regular classroom all day.
How a 20-to-1 ratio can coexist with a class of 28
Return to the school with 600 students and 30 teacher positions. Its ratio is 20 to 1.
If several teachers provide specialized services or teach small groups, the regular classroom teachers may each serve more than 20 students. One fourth-grade class could have 28 students while a reading specialist works with six students at a time.
Middle and high school class sizes also vary by course. A required English class may be large while an advanced language or music class is small.
What the ratio shows
The ratio gives a broad view of teacher staffing compared with enrollment. A lower ratio may come from smaller classes, more specialists, or more teachers serving small groups.
A change over time shows that enrollment, teacher staffing, or both have changed. The underlying enrollment and teacher totals show which one moved.
How to find the class size
For elementary school, the useful number is the current class size in your child's grade. For middle or high school, it is the enrollment in the specific required courses your child will take.
Schools and districts may publish class-size reports or staffing presentations. The enrollment office or school can also provide current grade-level or course information. Class sizes can change after the year begins as students enroll, leave, or move between sections.
