Standardized Mean Effect Size Calculator

How to use Standardized Mean Effect Size Calculator

Difference exact rational means of the parsed binary numbers, then divide by a shifted pooled sample standard deviation. Hedges g multiplies d by Γ(df/2)/(√(df/2)Γ((df−1)/2)), evaluated by a stable half/integer recurrence.

1. Enter group a observations, group b observations.
2. Choose the stated convention and check the units and supported model.
3. Calculate, inspect the result, then copy or download it.

Good to know

• 2–1000observations per group, nonzero pooled variation. Independent equal-variance pooled-SD standardization only; no paired-design correction, p value or universal practical-importance label.
• Runs locally. Text/JSON fields are capped at30,000 characters; stricter page-specific and numeric-string limits also apply. Numeric inputs are bounded to magnitude1e15 and nonzero magnitude at least1e-100 unless an exact-string mode states otherwise. Approximate summaries use12 significant digits; CSV numeric cells retain the complete stored value and potentially formula-like string cells gain a protective apostrophe; unsupported, non-finite or detected underflow states return an error.