Calculate richness, Shannon diversity, Simpson diversity and evenness.
Summarise the species counts in one sample. Your results can be printed or downloaded for field use.
Enter your measurements, then calculate.
Method and assumptions
Each line represents one species. Duplicate names are merged (ignoring case); zero-count species do not increase richness. With p = species count ÷ total: Shannon H = −Σ p ln(p), Simpson concentration D = Σ p², Gini–Simpson diversity = 1 − D, inverse Simpson = 1 ÷ D, and Pielou evenness = H ÷ ln(richness). These use relative-abundance plug-in estimates, not the unbiased n(n−1) variant. Evenness is undefined for fewer than two species. Compare similarly sampled communities, not unequal effort without adjustment. vegan ecological-diversity documentation defines these variants.
Instructions
- In One species and integer count per line (name, count), enter each species with its observed count.
- Include actual observations from one consistently sampled community.
- Select Calculate to view richness, diversity and evenness.
- Use Print result or Download CSV to retain the index values and sample details.
Understanding your results
Ten oak, ten birch and ten hazel give three observed species with equal counts. Evenness is high because no species dominates. Richness counts species with positive counts; it does not describe habitat quality on its own. The displayed Simpson variants use different conventions, so check which one another study reports.
What to do if evenness is undefined or a species appears merged
Evenness needs at least two positive-count species. Duplicate names are combined without case differences, so use consistent names and check spelling. Only enter whole, nonnegative counts; compare datasets collected with similar effort.
Using this tool in your browser
This tool handles your entries in your browser with JavaScript enabled and does not save them automatically. Use the download or print controls described in the instructions to keep a copy before closing or reloading the page. On a phone, your browser controls where downloads go and which print options are available.
Summary
Keep the raw species counts alongside the indices so the result remains understandable.