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Heritability Calculator (H², h² and Realised)

Broad-sense and narrow-sense heritability from variance components, or realised heritability from a selection experiment via the breeder’s equation.

Method

Additive genetic variance V_A

Dominance + epistatic variance V_D + V_I

Environmental variance V_E

Population mean (selection mode)

Mean of selected parents

Mean of their offspring

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How it works

H² = V_G ÷ V_P · h² = V_A ÷ V_P · realised h² = R ÷ S

Heritability is the share of phenotypic variation in a population explained by genetic variation — not how “genetic” a trait is in an individual. Narrow-sense h² uses only additive variance, which is what predicts response to selection through the breeder’s equation R = h²S. Values are population- and environment-specific.

Worked example

V_A = 12, V_D = 4, V_E = 14: V_P = 30, h² = 0.40, H² = 0.53. Selection: S = 12, R = 5 → realised h² = 0.42.

Frequently asked questions

Does high heritability mean environment does not matter?

No — it means environmental variation was small in that population. Change the environment and heritability changes too.

Typical values?

Human height ~0.8, milk yield in cattle ~0.3, litter size in pigs ~0.1.

Related calculators

Hardy-Weinberg Equilibrium Calculator

Work out allele and genotype frequencies under Hardy-Weinberg equilibrium from a dominant allele frequency p or from the frequency of the recessive phenotype q².

Allele Frequency Calculator

Count homozygous and heterozygous individuals to get the dominant and recessive allele frequencies and the genotype frequencies of a population.

Variance Calculator

Paste a list of numbers to get the sample and population variance, plus the standard deviation, mean and count — with the n vs n−1 difference explained.

For teaching and planning — verify against your lab protocol and instrument documentation.