Word and Letter Frequency Calculator
Analyze the frequency of every word and letter in your text.
Useful for writing analysis, cryptography, linguistics, and SEO keyword density.
Letter Frequency in English The most common letter in English is E, appearing about 12.7% of the time. The order of frequency is approximately: E T A O I N S H R D L C U M W F G Y P B V K J X Q Z. This distribution was first studied systematically by Samuel Morse in the 1830s in the United States when designing Morse code — the most common letters got the shortest codes.
Word Frequency The most common English word is “the,” appearing in roughly 7% of all text. The top 100 words account for about 50% of all written English. The top 1,000 words cover about 80%. This follows Zipf’s Law: the frequency of any word is inversely proportional to its rank.
Zipf’s Law Discovered by George Kingsley Zipf in 1935, this law states that in any large text, the most frequent word appears about twice as often as the second most frequent, three times as often as the third, and so on. This pattern appears in virtually every human language.
Applications Cryptography: frequency analysis is the primary tool for breaking substitution ciphers. If E is the most common letter and Q appears most often in a ciphertext, Q likely represents E. SEO: keyword density analysis helps optimize web content. Linguistics: comparing letter frequencies across languages reveals structural differences. Authorship analysis: unique word frequency patterns can help identify anonymous authors.