Heritability Calculator

Heritability Calculator. Heritability measures how much of the variation in a trait — like height, intelligence, or crop yield — is explained by genetics rather than environment. Select your Calculation Type (Broad-Sense H², Narrow-Sense h², Twin Study, or Breeding Response), then enter the corresponding variance or correlation values to get the Heritability Coefficient, Heritability Percentage, Environmental Variance, and an plain-language Interpretation of the result. Also try the calculate Frequency of p (dominant allele), Frequency of q (recessive allele) & Total population size — Allele Frequency.

Heritability Calculator inputs

Results

Heritability Coefficient

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Heritability Percentage

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Environmental Variance (Ve)

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Interpretation

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What is the difference between broad-sense and narrow-sense heritability?

Broad-sense heritability (H²) measures the proportion of total phenotypic variance due to all genetic factors, while narrow-sense heritability (h²) measures only the additive genetic effects that are passed from parents to offspring. See also our calculate Allele p frequency, Allele q frequency & Expected AA (p²) — Hardy-Weinberg Equilibrium.

What do heritability values mean?

Heritability values range from 0 to 1. A value of 0.8 means 80% of the variation in a trait is due to genetic factors, while 20% is environmental. Higher values indicate stronger genetic influence on the trait.

How is heritability calculated from twin studies?

Twin studies use correlations between monozygotic (identical) and dizygotic (fraternal) twins. The formula is h² = 2(rMZ - rDZ), where rMZ is the correlation for identical twins and rDZ is the correlation for fraternal twins.

Can heritability exceed 1.0?

No, heritability cannot exceed 1.0 by definition, as it represents a proportion of variance. Values above 1.0 indicate calculation errors or invalid input parameters.

What is environmental variance?

Environmental variance (Ve) represents the portion of phenotypic variation caused by environmental factors rather than genetics. It equals total phenotypic variance minus genetic variance (Ve = Vp - Vg).

How accurate are heritability estimates?

Heritability estimates are population-specific and environment-specific. They represent the proportion of variance in a particular population under specific conditions, not the absolute genetic contribution to a trait.

What is breeding response and how does it relate to heritability?

Breeding response (R) is the change in trait mean after selection. It relates to heritability through the formula h² = R/S, where S is the selection differential (difference between selected parents and population mean). You might also find our Punnett Square Calculator (Monohybrid) useful.