Effect Size (Cohen's d)
Calculate Effect Size (Cohen's d) instantly with the exact formula and a worked example.
Effect Size (Cohen's d)
Group 1 mean
Group 2 mean
Group 1 standard deviation
Group 2 standard deviation
Group 1 size
Group 2 size
Cohen's d
0.333333
Pooled SD
15
Hedges g
0.329
Effect size
Small
More about: Effect Size (Cohen's d)
What it calculates
The “Effect Size (Cohen's d)” calculator computes Cohen's d from 6 parameters: group 1 mean, group 2 mean, group 1 standard deviation, group 2 standard deviation, group 1 size, group 2 size.
A core calculation for studying, engineering tasks, and checking solutions.
Example calculation
With parameters Group 1 mean = 105, Group 2 mean = 100, Group 1 standard deviation = 15, Group 2 standard deviation = 15, Group 1 size = 30, Group 2 size = 30 the result is 0.3333.
How to use
- Enter group 1 mean, group 2 mean, group 1 standard deviation, group 2 standard deviation, group 1 size and group 2 size — each field above is adjustable with a slider.
- Cohen's d 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 Effect Size (Cohen's d) calculated?
The Effect Size (Cohen's d) calculator computes Cohen's d from group 1 mean, group 2 mean, group 1 standard deviation, group 2 standard deviation, group 1 size, group 2 size. Enter your values above and the exact formula is applied instantly; a worked example with real numbers is shown below.
Is the Effect Size (Cohen's d) 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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