This online calculator calculates measure known as fitness score, of how given text is similar to a typical English text. It uses frequencies of unigrams, bigrams and trigrams 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.

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.