The species diversity index conforms to the following formula:

, the summation is for i=1 to g,

where p_i = n_i/N; n_i = Total number of individuals in the i ^th taxa; N = total of all individuals found in the sample; g = total number of taxa in the sample; H = species diversity index.

The Evenness index conforms to the following formula:

where J= Evenness; H= Species diversity index; log₁₀ g = the log of the number of taxa in the sample.

The Percent similarity index (psc) is described mathematically as follows:

where a and b are, for a given taxa, percentages of the total sample A and B which that taxon represents. The absolute value of their difference is summed over all taxa.