stats
Effect Size Calculator
Cohen's d, Cohen's h, and Eta Squared (η²) — magnitude bar with practical significance interpretation.
Inputs
Effect Size Type
Effect magnitude
Statistical significance (p-value) tells you if an effect exists. Effect size tells you how large it is.
Results
Pooled SD s_p—
Cohen's d—
Interpretation—
|d| < 0.2 negligible · 0.2 small · 0.5 medium · 0.8 large · ≥ 1.2 very large
d = (x̄₁−x̄₂)/s_p · s_p = √[Σ(n_k−1)s_k²/(n₁+n₂−2)]