Number Needed to Treat (NNT)
Calculate Number Needed to Treat (NNT) instantly with the exact formula and a worked example.
Number Needed to Treat (NNT)
Event rate in control group%
Event rate in treatment group%
NNT
20
Absolute risk reduction (ARR)
5%
Relative risk reduction (RRR)
25%
Exact 1/ARR
20
More about: Number Needed to Treat (NNT)
What it calculates
The “Number Needed to Treat (NNT)” calculator computes NNT from 2 parameters: event rate in control group (%), event rate in treatment group (%).
A core calculation for studying, engineering tasks, and checking solutions.
Example calculation
With parameters Event rate in control group = 20 %, Event rate in treatment group = 15 % the result is 20.
How to use
- Enter event rate in control group and event rate in treatment group — each field above is adjustable with a slider.
- NNT is calculated automatically as you type.
- Check the worked example below to see the formula applied to real numbers.
- Copy the result or bookmark this calculator.
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FAQ
How is Number Needed to Treat (NNT) calculated?
The Number Needed to Treat (NNT) calculator computes NNT from event rate in control group, event rate in treatment group. Enter your values above and the exact formula is applied instantly; a worked example with real numbers is shown below.
Is the Number Needed to Treat (NNT) calculator free?
Yes. It is completely free, needs no signup, runs entirely in your browser, and sends no data to any server.
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