Species Diversity Index Calculator (Shannon-Wiener)
Calculate Shannon-Wiener diversity index, Simpson index, species richness, and Pielou evenness from species count data.
Ecology biodiversity tool.
Shannon-Wiener Index (H) The most widely used diversity index in ecology.
H = -sum( pi × ln(pi) )
Where pi = ni / N (proportion of species i out of total N individuals). A higher H means more diversity. Scale: H < 1.5 = low diversity | 1.5–3.0 = moderate | > 3.0 = high diversity
Pielou Evenness (J) Measures how evenly individuals are distributed across species.
J = H / ln(S)
Where S = number of species. J ranges from 0 (one species dominates) to 1 (perfectly even).
Simpson Index (1-D) Probability that two randomly selected individuals belong to different species.
D = sum( pi² ) Simpson = 1 - D
Ranges from 0 (no diversity) to 1 (maximum diversity).
Species Richness Simply the count of distinct species (S) — the most basic diversity measure.
How to Enter Data Enter the count of individuals for each species, separated by commas. Example: 45,30,15,8,2 means five species with those counts.