Enter the control group % and the experiment group % into the NNT calculator. The calculator will display the total number of patients that need to be treated to achieve an endpoint.

## Number Needed to Treat Formula

The following formula is used to calculate the total number of patients that need to be treated in order to achieve a result.

NNT=1/ARR

- Where NNT is the number of patients that need to be treated
- ARR is the absolute risk reduction

Further more, ARR can be calculated through the following equation.

ARR=CER – EER

- Where CER is the control event rate
- EER is the experiment event rate

## Number Needed to Treat Definition

The number needed to treat is defined as the total estimate of people that need to be treated of a disease in order to mitigate transmission.

## How to calculate number needed to treat?

How to calculate a number needed to treat

**First, measure the control event rate**This will be the percent treated in the control event.

**Next, measure the experiment event rate**This will be the percent treated in the experiment.

**Lastly, calculate the NNT**Using the formula above and the information from steps 1-2 to calculate the NNT

## FAQ

**What is NNT?**

NNT stands for number needed to treat. It’s a term used in medicine to describe the total number of patients needed to be treated in order to achieve a given result.