Enter your Number of Different Species and each species population count to calculate the Simpson's Diversity Index (D) — a measure of how evenly distributed your species are. You'll also get the Total Organisms, a plain-language Diversity Level, and the Simpson's Reciprocal Index (1/D) to show effective species richness.
Simpson's Diversity Index (D)
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Total Organisms
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Diversity Level
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Simpson's Reciprocal Index (1/D)
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Simpson's diversity index (D) is a measure of diversity that takes into account both the number of species present and their relative abundance. It ranges from 0 to 1, where values closer to 0 indicate higher diversity.
Simpson's index is calculated using the formula D = Σ(pi²), where pi is the proportion of each species in the total population. The index sums the squared proportions of all species present.
A high Simpson's diversity index (closer to 1) indicates low diversity, meaning the community is dominated by one or few species. This suggests less ecological stability and resilience.
A low Simpson's diversity index (closer to 0) indicates high diversity with many species present in relatively equal proportions. This suggests a more stable and resilient ecological community.
Enter the number of species in your community, then input the population count for each species. The calculator will compute the index and provide interpretation of the diversity level.
Simpson's reciprocal index (1/D) is the inverse of Simpson's diversity index. Unlike the standard index, higher values indicate greater diversity, making it more intuitive to interpret.
This calculator supports analysis of up to 20 different species. For studies with more species, you can group similar or rare species together for analysis.