Character Frequency
Analyze how often each character appears in your text
Input Text
Options
85
Total Chars
28
Unique Chars
'⎵' (16×)
Top Char
Frequency Chart (28 chars)
About the Character Frequency Analyser
This character frequency analyser counts every character in a text and shows counts, percentages and a bar chart. It is the standard first step in breaking a substitution cipher and a quick way to spot unexpected characters in data.
Character frequency analysis counts occurrences of each individual character rather than each word. In English, E is the most common letter at around 12%, followed by T, A, O, I and N — a distribution stable enough across any long text to be useful.
That stability is what breaks simple substitution ciphers. Because such ciphers replace letters consistently, the frequency pattern survives encryption: the most common symbol in the ciphertext is very likely E, and the shape of the whole distribution guides the rest.
It is also useful for data inspection. An unexpected count of tabs, non-breaking spaces or control characters in a supposedly clean file explains a lot of otherwise mysterious parsing failures.
How to use the Character Frequency Analyser
- Paste your text. Enter the text or ciphertext to analyse.
- Read the counts. See each character with its count and percentage.
- Compare to English. Match the distribution against the usual E, T, A, O, I, N ordering.
- Look for oddities. Check for unexpected tabs, control characters or invisible spaces.
Character Frequency Analyser features
- Count and percentage for every distinct character
- Ordered most to least frequent
- Bar chart of the distribution
- Case-sensitive or case-insensitive counting
- Surfaces tabs, control characters and non-breaking spaces
- Runs in your browser; the text is not uploaded
Frequently asked questions
What does character frequency analysis measure?
It counts how often each individual character appears, rather than each word, and shows the count alongside its share of the total. In English prose the ordering is stable enough to be useful: E is around 12%, followed by T, A, O, I and N.
How does this help with a substitution cipher?
A simple substitution cipher replaces each letter consistently, so the frequency pattern survives encryption even though the letters change. The most common symbol in the ciphertext is very likely E, and the shape of the rest of the distribution suggests the next candidates.
Can I ignore capitalisation?
Yes. There is a toggle for case-insensitive counting, which folds A and a into one entry. Leave it off when you care about the distinction, such as checking how often a text starts sentences with a particular letter.
Why would I use this on data rather than prose?
Because it makes invisible characters visible. An unexpected count of tabs, non-breaking spaces or control characters in a supposedly clean file usually explains a parsing failure that looks inexplicable otherwise.
Is there a length limit?
There is no fixed cap. Counting is a single pass over the text in your browser, so the practical limit is what your browser will hold in a textarea comfortably.