Student-Teacher Ratio Calculator

Calculate the student-to-teacher ratio, students per teacher, and teachers per 100 students for any classroom or school.

Student-Teacher Ratio

Enter students and teachers below

Number of Students

Number of Teachers

Student-Teacher Ratio

Students per Teacher

Teachers per 100 Students

Formula

Ratio = Students : Teachers
SPT = Students ÷ Teachers
TPH = (Teachers ÷ Students) × 100

A lower ratio generally indicates more individual attention per student. Most education research suggests 15–20:1 as an optimal range.

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Pro Tips

Class sizes above 30:1 are generally considered challenging for effective teaching.

Private schools often target ratios of 10:1 or lower for premium instruction.

The OECD average student-teacher ratio is about 15:1 for primary education.