Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Number Needed to Treat (NNT) Calculator

Calculate the number of patients who must be treated to prevent one additional bad outcome, from the control and treatment event rates. A key measure of clinical effectiveness.

Control Group Event Rate (%)

Treatment Group Event Rate (%)

Probability

Confidence Interval Calculator

Computes the range of values likely to contain a true population mean at your chosen confidence level. Use it when reporting survey results, clinical trial outcomes, or any estimate derived from a sample.

Sample Mean

Sample Standard Deviation

Sample Size (n) (observations)

Confidence Level

Distribution Type

Key differences

	Number Needed to Treat (NNT) Calculator	Confidence Interval Calculator
Category	Statistics	Probability
Inputs required	2	5
Result	Number Needed to Treat (patients)	Margin of Error (±)
What it does	Calculate the number of patients who must be treated to prevent one additional bad outcome, from the control and treatment event rates. A key measure of clinical effectiveness.	Computes the range of values likely to contain a true population mean at your chosen confidence level. Use it when reporting survey results, clinical trial outcomes, or any estimate derived from a sample.