Species Diversity (Shannon) Calculator

Work out species diversity (shannon) instantly with clear inputs, formula shown and shareable results.

About Species Diversity (Shannon) Calculator

Sums the proportional abundances times their logarithms to give the Shannon index, with evenness and the effective number of species.

Formula

Shannon index

H = -sum(pi x ln pi); evenness = H / ln(S); effective species = e^H

Worked example

With the default values below, Species Diversity (Shannon) Calculator returns Shannon diversity index of 1.2799. Change any input above and every figure here is recalculated in your browser.

Inputs used

Individuals per species: 40, 30, 20, 10
Logarithm baseone of Natural log (nats), Log base 2 (bits), Log base 10: Natural log (nats)

Results

Shannon diversity index: 1.2799
Pielou's evenness: 0.9232
Species richness: 4
Effective number of species: 3.596

Step by step

1Values used
2Shannon index
3Shannon diversity index= 1.2799
4Pielou's evenness= 0.9232
5Species richness= 4
6Effective number of species= 3.596

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What does the index actually measure?

Uncertainty in predicting the species of a randomly drawn individual, combining richness and evenness.

Why report effective species?

The exponential of H is in intuitive species units and behaves linearly when communities are combined.