This calculator uses the principle of Hardy-Weinberg equilibrium and the binomial distribution to determine the probability that a variant detected in a specified number of individuals in a population-based cohort could account for a specific percentage of cases or mutations for a genetic disease or phenotype. The Express versionis recommended for confident users of the program. The non-Express version should be used by less experienced users or if the genetic architecture of the disease or phenotype is less certain. Reading of the usage notes is especially recommended for this program.