Number Needed to Treat Calculator

Calculate the number needed to treat, absolute risk reduction, and relative risk reduction from control and treatment event rates

Frequently Asked Questions

What does number needed to treat mean?

It is how many patients must be treated for one additional person to benefit compared with a control group. Lower numbers mean more effective treatments.

How is it related to absolute risk reduction?

The number needed to treat is the reciprocal of the absolute risk reduction expressed as a fraction.

Why report both absolute and relative risk reduction?

Relative risk reduction can look large even when the absolute benefit is small, so reporting both gives an honest picture.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.