This online calculator computes text "fitness". That is, how similar the given text to other texts written in English language.

This online calculator calculates measure known as fitness score, of how given text is similar to a typical English text. It uses logarithms of probabilities with normalization to calculate fitness score. The reference frequencies are calculated from Leipzig Corpora Collection and can be downloaded from http://practicalcryptography.com/cryptanalysis/text-characterisation/quadgrams/. The less value you get, the better.