Character frequency counter

Every distinct character in your text is counted and ranked, commonest first, with the share of the total. Spaces and line breaks are included and labelled rather than hidden.

Frequency analysis is the oldest technique in cryptanalysis and it still works on simple substitution ciphers, because a substitution changes which symbol stands for E without changing how often it appears. In ordinary English, E is about 12 percent of letters, then T, A, O, I and N; if your ciphertext has one symbol at roughly 12 percent, that is your E. The method breaks on anything with a polyalphabetic key and on very short texts, where a single unusual word skews everything. It is also a quick way to spot a stray character — a non-breaking space or a smart quote sitting in data where it should not be.