Compare calculators
Both calculators run independently β change the inputs on either side to compare results.
Statistics
Cohen's d Effect Size Calculator
Calculate Cohen's d β the standardized difference between two group means in pooled standard deviation units. Measures how big an effect is, not just whether it is significant.
Probability
Sample Size Calculator
Determine the minimum sample size needed for a survey or experiment given your confidence level, margin of error, and population size. Prevents under-powered studies and over-budgeted data collection.
Key differences
| Cohen's d Effect Size Calculator | Sample Size Calculator | |
|---|---|---|
| Category | Statistics | Probability |
| Inputs required | 4 | 4 |
| Result | Cohen's d | Required Sample Size (samples) |
| What it does | Calculate Cohen's d β the standardized difference between two group means in pooled standard deviation units. Measures how big an effect is, not just whether it is significant. | Determine the minimum sample size needed for a survey or experiment given your confidence level, margin of error, and population size. Prevents under-powered studies and over-budgeted data collection. |