Enter the number of individuals of each species of up to 5 different species into the calculator to determine Simpson’s diversity index.

## Simpson’s Diversity Index Formula

The following formula is used to calculate Simpson’s Diversity Index.

D = 1 – [ sum(n*(n-1) / N*(N-1) ]

• Where D is the diversity index
• n is the number of individuals of each species
• N is the total number of individuals of all species

## Simpson’s Diversity Index Definition

What is Simpson’s Diversity Index? Simpson’s diversity index, or sometimes just referred to as the diversity index, is a measure that outlines how many different types there are in a dataset that can take into account the phylogenetic relations among the individuals distributed amount those types. In other words, biodiversity in different aspects of species.

## Example Problem

How to calculate Simpson’s Diversity Index?

1. First, determine the number of individuals of each species.

For this example, there are 5 different species with counts of 10,20,15,12,8.

2. Next, determine the total number of individuals of all species.

Adding together the numbers from step 1, we have a total of 65.

3. Next, determine the sum of sum(n*(n-1)) of each individual species count.

For this example, that would be 10*(9)+20*(19)+15*(14)+12*(11)+8*(7) = 868.

4. Next, determine the value of N*(N-1) where N is the total number of individuals of all species calculated in step 2.

N*(N-1) = 65*(65-1) = 4160.

5. Finally, calculate the diversity index.

Using the formula above, we find the diversity index to be D = 1 – (868/4160) = .7913.