What Is Letter Frequency Analysis?

Letter frequency analysis counts how often each letter appears in a piece of text. It’s one of the oldest techniques in cryptography—used for centuries to crack substitution ciphers—and remains valuable today for linguists, writers, students, and puzzle enthusiasts.

In standard English text, the letter E appears most frequently (about 12-13% of all letters), followed by T, A, O, I, and N. Understanding these patterns helps with everything from solving crossword puzzles to optimizing keyboard layouts.

How to Use This Tool

1. Paste or type your text into the input box above
2. Watch the analysis update in real time as you type
3. Switch between views to explore your results:
   • Bar Chart shows a visual comparison of letter frequencies
   • Table provides exact counts sorted by frequency
   • A-Z Grid displays every letter with heat-map coloring

Practical Uses for Letter Frequency Analysis

Cryptography and puzzles: Frequency analysis is the foundation of breaking simple ciphers. If a coded message has one symbol appearing 13% of the time, it likely represents the letter E.

Language identification: Different languages have distinct frequency signatures. German has high frequencies of E, N, and I. French shows high E, A, and S. Comparing your text’s pattern against known distributions can identify the language.

Writing style analysis: Compare the letter distributions across different authors or genres. Technical writing, poetry, and casual prose each produce distinctive frequency fingerprints.

SEO and content optimization: Certain letter patterns correlate with readability. Analyzing your content’s letter distribution can reveal over-reliance on specific words or phrases.

Education: Letter frequency is a core topic in statistics, probability, and information theory courses. This tool provides hands-on demonstration of these concepts.

English Letter Frequency (Reference)

The typical frequency ranking for English text is: 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. However, actual frequencies vary based on the type of text—formal writing, social media posts, and technical documentation each produce slightly different distributions.

Frequently Asked Questions

What is the most common letter in English?

The letter E is the most common in English, appearing roughly 12.7% of the time across a large sample of text.

Does this tool count uppercase and lowercase separately?

No. The analyzer treats uppercase and lowercase as the same letter, giving you a combined frequency count for each of the 26 letters.

Can I analyze text in other languages?

Yes. The tool counts the 26 English alphabet letters (A-Z) in any text you provide. Characters outside this range (accented letters, non-Latin scripts, numbers, punctuation) are excluded from the letter frequency count.

What are the least common letters in English?

Z, Q, X, J, and K are the five least common letters in standard English text, each appearing less than 1% of the time.

Try our free letter counter → to get full word, character, and sentence counts for your text.