Letter frequency tells you how often each letter appears in a message. Open the frequency view to see counts and percentages for the current normalized input. The chart can help you notice patterns, but it does not identify the language, author, or correct solution.
Count letters, not punctuation
A small input you can check by hand
HELLO, WORLD!Shift 3; count frequencies in normalized input HELLO, WORLD!KHOOR, ZRUOG!| Letter | Count | Share of 10 letters |
|---|---|---|
| D | 1 | 10% |
| E | 1 | 10% |
| H | 1 | 10% |
| L | 3 | 30% |
| O | 2 | 20% |
| R | 1 | 10% |
| W | 1 | 10% |
There are 10 letters in total. The comma, space, and exclamation mark do not count. A letter’s share is 100 × its count ÷ total letters. Letters that do not appear have a count of zero. Rounding may put the displayed percentages just above or below 100%, while the whole-number counts remain exact.
What can the pattern tell you?
L is the most common letter in HELLO, WORLD!. That is a fact about this message, not about English as a whole. A short phrase, name, or carefully chosen puzzle can have a very different pattern from a longer passage.
A simple substitution changes the labels on the counts: every occurrence of one letter becomes its partner. Transposition moves letters without changing their counts. A repeating-key cipher can shift the same letter in different ways, so its chart needs a different interpretation.
If there are no letters to count
A sample with no A–Z letters has a total of zero. Enter a message containing letters before comparing percentages. Punctuation on its own gives you no letter-frequency pattern to analyze.
Count a short word yourself
Count the A–Z letters in BANANA! before opening the frequency view.