Effective Population Size Calculator

Calculate effective population size (Ne) accounting for sex ratio, variance in offspring, population fluctuations, and overlapping generations.

Population Parameters

Census Population (N)

Number of Males

Number of Females

Male Offspring Variance

Female Offspring Variance

Mean Offspring per Individual

Historical Population Sizes (comma-separated)

For calculating Ne from population fluctuations

Generation Overlap (0-1)

Conservation Thresholds:

Ne > 50: Short-term viability | Ne > 500: Long-term sustainability

Population Viability

Marginal - At Risk

454.5

Effective Ne

0.455

Ne/N Ratio

Ne by Method

Unequal Sex Ratio

4NmNf/(Nm+Nf)

960.0

Variance in Offspring

(4N-2)/(2+V/k)

1142.3

Fluctuating Size

Harmonic mean

454.5

Overlapping Generations

N(1-overlap)

700.0

Genetic Consequences

Het Loss per Generation0.1100%

Time to 50% Het Loss630.1 gen

Inbreeding Rate0.1100% per gen

F after 10 Generations0.0109

Drift Variance per Gen0.000275

Population Details

Census Population1000

Males : Females400 : 600

Sex Ratio (M/F)0.667

Conservation Thresholds

Short-term viable (Ne > 50)

Long-term sustainable (Ne > 500)

Ideal (Ne > 1000)

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Editorial Note

MyCalcBuddy Editorial Team

This page is maintained as an educational calculator reference.

ðŸ“š

Formula Source: Standard Mathematical References

by Various

ðŸ”„Last reviewed: May 2026

âœ“Formula checks are based on standard references and internal QA review.