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

Marginal - At Risk

454.5

Effective Ne

0.455

Ne/N Ratio

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

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

Census Population1000

Males : Females400 : 600

Sex Ratio (M/F)0.667

Short-term viable (Ne > 50)

Long-term sustainable (Ne > 500)

Ideal (Ne > 1000)