Biology and Ecology
Shannon Diversity Index Calculator
Shannon Diversity Index Calculator calculate Shannon diversity, maximum diversity, Pielou evenness, richness, and total abundance from category counts with a selectable logarithm base.
Biology and Ecology
Shannon Diversity Index Calculator
Calculate Shannon diversity, maximum diversity, Pielou evenness, richness, and total abundance from category counts with a selectable logarithm base.
Formula
Shannon index H = -sum(p_i x log(p_i)); evenness J = H / log(richness), using the selected log base consistently.
About the Shannon Diversity Index Calculator
Calculate Shannon diversity, maximum diversity, Pielou evenness, richness, and total abundance from category counts with a selectable logarithm base.
How the Shannon Diversity Index Calculator Works
Positive counts are divided by total abundance to form proportions, each information term is summed in the selected base, and observed diversity is compared with its equal-abundance maximum.
Formula
Shannon index H = -sum(p_i x log(p_i)); evenness J = H / log(richness), using the selected log base consistently.
The calculation runs in your browser. Values are validated for required ranges, compatible units, and method-specific restrictions before results are displayed.
Required Inputs
- Category or species counts (required).
- Logarithm base (required).
Results Reported
The result panel reports the final answer and the intermediate quantities needed to check the calculation:
- Shannon diversity index
- Maximum diversity for richness
- Pielou evenness
- Observed category richness
- Total abundance
- Effective number of categories
Shannon Diversity Index Calculator Example
Select Example Data in the calculator to load this reproducible input set:
| Input | Example value |
|---|---|
| Category or species counts | 18, 12, 7, 3 |
| Logarithm base | e |
How to Use the Calculator
- Confirm that the calculator title and formula match the quantity you need.
- Enter every required value using the unit shown with its field.
- Select Example Data to inspect a valid input set, or enter your own values and select Calculate.
- Review all reported values and the displayed formula before using the answer.
- Use Copy Result or Download CSV when you need a reusable record.
Accuracy and Limitations
Sampling design, detectability, taxonomy, effort, and zero or unobserved categories affect interpretation. Natural logarithms are used and only positive observed counts contribute.
Keep units consistent, use measurements that represent the actual situation, retain full precision during the calculation, and round only the final answer. Professional decisions may require current official rules, field measurements, laboratory methods, or specialist review.
Frequently Asked Questions
What does the Shannon Diversity Index Calculator calculate?
Calculate Shannon diversity, maximum diversity, Pielou evenness, richness, and total abundance from category counts with a selectable logarithm base.
Which formula does the Shannon Diversity Index Calculator use?
Shannon index H = -sum(p_i x log(p_i)); evenness J = H / log(richness), using the selected log base consistently. Positive counts are divided by total abundance to form proportions, each information term is summed in the selected base, and observed diversity is compared with its equal-abundance maximum.
What should I check before using the Shannon Diversity Index Calculator result?
Sampling design, detectability, taxonomy, effort, and zero or unobserved categories affect interpretation. Natural logarithms are used and only positive observed counts contribute.