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Number needed to treat (NNT)

How effective is a clinical treatment? Because many people find it hard to think about small fractions, these kind of data are better understood when converted to the Number Needed to Treat or NNT. Enter the number of patients in each group who had the "good" or "bad" outcome, and this calculator will convert to NNT and explain the results.

Enter the actual number of patients in each group. Don't enter fractions, percentages, or rates per 1000 or some other value.

Good Outcome Bad Outcome
Desired confidence level: