# Teacher Student Ratio Calculator

> Calculate students per teacher from enrolment and full-time-equivalent staff, and how many teachers you need to meet a target ratio.

Category: Education · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/teacher-student-ratio-calculator

The pupil–teacher ratio is the number of students divided by the number of full-time-equivalent teachers. Enter your target ratio to see the staffing it implies.

Also called: Pupil–teacher ratio calculator, Student–teacher ratio calculator.

## Inputs
- Number of students (default 600)
- Teachers (full-time equivalent) (default 24)
- Target students per teacher (default 20; optional)

## Results
- Students per teacher
- Ratio
- Teachers per 100 students
- Teachers needed for target
- Additional teachers needed

## Formula

```
Students per teacher = Students ÷ FTE teachers;  Teachers needed = ⌈Students ÷ Target⌉
```

Where:
- FTE teachers: full-time-equivalent teaching staff
- Target: the maximum students per teacher you must meet

## Worked example
1. 600 ÷ 24 = 25 students per teacher (25 : 1).
2. At 20 : 1, 600 ÷ 20 = 30 teachers are needed.
3. 30 − 24 = 6 more teachers.

**Result:** With 24 teachers for 600 students the ratio is 25 : 1; reaching 20 : 1 needs 6 more teachers.

## What the result means

The pupil–teacher ratio is not the same as class size: teachers also have planning time and non-class duties, so average classes are usually larger than the ratio.

## Assumptions and limits
- Teachers are counted as full-time equivalents.
- Whether support staff, heads or specialists count as teachers depends on the reporting rules you follow.

## Questions

### Is pupil–teacher ratio the same as class size?

No. Class size is students in one room; the ratio spreads all students over all teachers, including those not teaching at that moment.

### How do I count part-time teachers?

Use full-time equivalents: a teacher working half a full timetable counts as 0.5.

## Related calculators
- [Ratio Calculator](https://calculators.geekmidst.com/calculators/ratio-calculator)
- [Classroom Capacity Calculator](https://calculators.geekmidst.com/calculators/classroom-capacity-calculator)
- [Academic Year Working Days Calculator](https://calculators.geekmidst.com/calculators/academic-year-working-days-calculator)

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/teacher-student-ratio-calculator