Letter Frequency Analyzer (English, German, French, Spanish)

Letter frequency is the simplest cryptanalysis technique — for substitution ciphers, the most common letter in the ciphertext is often "e" if the language is English (~12.7%). This analyzer counts letters in your text and compares against published baselines for English, German, French, and Spanish.

How to use the Letter Frequency Analyzer (English, German, French, Spanish)

Paste text, pick a language baseline. Output shows letter frequency table with bars and deviation from baseline.

Counting letters for cryptanalysis and more

Letter frequency is the oldest tool in cryptanalysis. In English, e is the most common letter at about 12.7%, followed by t and a. A simple substitution cipher preserves those frequencies, so the most common symbol in the ciphertext is very likely e. Frequencies also differ by language, which can hint at what language an unknown text is written in.

This counts every letter in your text and charts it against published baselines for English, German, French, and Spanish, showing the deviation from each. It is a natural starting point for breaking substitution ciphers and for guessing the language of a sample. To analyse whole-word frequency rather than individual letters, see the word frequency counter.

Common use cases

• Cryptanalysis — match ciphertext letter frequencies to crack a substitution cipher.
• Language guessing — compare a sample against four language baselines.
• Puzzle solving — get letter counts for cryptograms and word games.
• Text fingerprinting — spot an unusual or skewed letter distribution.
• Teaching — demonstrate why e dominates English text.