Number Needed to Treat Calculator

This simple number needed to treat calculator allows you to calculate the average number of patients who need to receive a specific treatment in order to prevent one additional adverse event.

For example, imagine a group of patients is given a new experimental drug, and it turns out that fewer die compared to patients who are only given a placebo. In this circumstance, it is possible to work out just how many patients need to be given the new drug (on average) before one life is saved - that is, before one patient avoids the adverse event of death. This figure is the number needed to treat.

To use this calculator, enter data for your control and experimental groups. The number needed to treat calculation requires the end point of an intervention to be the presence or absence of an adverse event (e.g., heart attack; extended hospital stay; death). You should enter this information into the Event and Non-event boxes.

Hit the "Calculate" button when you're ready to perform the calculation.

Enter Your Data Below
  Event (Bad) Non-event (Good)    
Control Group    
Experimental Group    

No calculation performed yet.

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