Microbiome Diversity Calculator
Calculate Shannon and Simpson diversity indices from taxon abundances.
About Microbiome Diversity Calculator
Shannon and Simpson answer different questions: Shannon responds strongly to the presence of rare taxa while Simpson responds to how dominant the most abundant taxon is. Evenness normalises Shannon by the maximum possible for that richness. Reporting one index alone can be misleading, because a community can be rich but heavily dominated, which the two indices characterise differently.
Formula
Microbiome Diversity
Shannon H = −Σ pᵢ ln pᵢ; Simpson D = 1 − Σ pᵢ²
- Shannon
- Weights rare taxa more heavily, sensitive to richness
- Simpson
- Weights abundant taxa more heavily, sensitive to dominance
Worked example
With the default values below, Microbiome Diversity Calculator returns Shannon Diversity Index of 1.2854. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Abundance of taxon 1minimum 0
- 450
- Abundance of taxon 2minimum 0
- 300
- Abundance of taxon 3minimum 0
- 150
- Abundance of taxon 4minimum 0
- 80
- Abundance of taxon 5minimum 0
- 20
Results
- Shannon Diversity Index
- 1.2854
- Simpson Diversity Index
- 0.6782
- Observed Richness
- 5
- Shannon Evenness
- 0.7987
- Total Reads
- 1,000
Step by step
- 1Values used
- 2Microbiome Diversity
- 3Shannon Diversity Index= 1.2854
- 4Simpson Diversity Index= 0.6782
- 5Observed Richness= 5
- 6Shannon Evenness= 0.7987
- 7Total Reads= 1,000
Assumptions and limits
- The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, 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
How is Microbiome Diversity calculated?
Shannon H = −Σ pᵢ ln pᵢ; Simpson D = 1 − Σ pᵢ² Shannon and Simpson answer different questions: Shannon responds strongly to the presence of rare taxa while Simpson responds to how dominant the most abundant taxon is. Evenness normalises Shannon by the maximum possible for that richness.
Why does Microbiome Diversity matter?
Reporting one index alone can be misleading, because a community can be rich but heavily dominated, which the two indices characterise differently.
What values do I need to enter?
This calculator takes 5 inputs: Abundance of taxon 1, Abundance of taxon 2, Abundance of taxon 3, Abundance of taxon 4, Abundance of taxon 5. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.