Trait Heritability Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 27, 2026Trait Heritability Calculator
What proportion of variation in a trait across a population comes from genetic differences versus environmental factors? This calculator computes broad-sense heritability (h┬▓) from variance components.
h┬▓ = Genetic Variance / (Genetic Variance + Environmental Variance)
Example
Genetic variance of 70, environmental variance of 30:
h┬▓ = 70 / (70 + 30) = 0.7 (high heritability)
A Critical, Widely Misunderstood Point
Heritability describes variation within a specific population under specific conditions - it does NOT describe how "genetic" a trait is for any given individual. A heritability of 0.7 doesn't mean 70% of an individual's trait value comes from their genes; it means 70% of the variation observed across the studied population traces back to genetic differences between individuals in that population, under the environmental conditions present at the time of study.
Why Heritability Can Change
Heritability estimates are specific to the population and environment studied - if environmental variation increases (say, due to more diverse living conditions), heritability for the same trait can decrease even though the underlying genetics haven't changed at all, since a larger share of the observed variation would now be attributable to that increased environmental variation.