- Hartley's formula
Hartley's formula to determine the amount of information contained in a message with length n.

- Huffman coding
This online calculator generates Huffman encoding for given frequency of occurrence of symbols.

This online calculator builds symbol frequency table for a given message

- Shannon Entropy
This online calculator computes Shannon entropy for a given event probability table and for a given message

- Wordpress plugin
With Planetcalc plugin for Wordpress you can easily insert any planetcalc calculator in your wordpress-based site or blog pages.