Result
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Facts and limits of this method
| Unique character | Every distinct kind of character is counted once, no matter how many times it repeats |
|---|---|
| Case-sensitive | "A" and "a" are two different characters |
| Not case-sensitive | "A" and "a" are folded into one before counting |
| "Ignore spaces and punctuation" | Removes spaces and a standard set of punctuation marks from the count |
When it misleads you
- Counting is done by code point, not by "visible" character — an emoji made of several code points, or a letter with a separately-composed diacritic, can be counted as several different characters instead of one visible one.
- The list of punctuation marks excluded by "ignore punctuation" is fixed (.,!?;:'"()[]{}-–—…«»„“) — uncommon symbols like an asterisk or ampersand aren't in that list and are counted as regular characters.
- A pangram (text using every letter of an alphabet) only produces exactly as many unique letters as the alphabet if there are no typos or stray characters — the counter counts literally everything in the input field, not a "corrected" alphabet.
- The uppercase and lowercase form of one letter are counted as different characters when case-sensitivity is on, even though they're conceptually "the same letter."
How it is calculated
The text is split into individual characters; if case-sensitivity is off, every letter is lowercased before the next step.
If "ignore spaces and punctuation" is on, spaces and a fixed set of punctuation marks are removed from the character list.
A frequency table is built for the remaining characters — how many times each one appears; the number of distinct keys in that table is the answer.
The most frequent character is the one with the highest value in the frequency table; ties are broken by whichever was found first.
Questions and answers
Why would I want to count unique characters specifically?
For example, to check a pangram (does the text use every letter of the alphabet), to gauge password diversity, or to find the most frequent character in a text or piece of code.
Do "A" and "a" count as one character or two?
It depends on the "case-sensitive" setting: on, they're two different characters; off, they're treated as the same one.
Does a space count as a character?
Yes, unless "ignore spaces and punctuation" is turned on — then a space is excluded from the count, same as punctuation marks.
Is my text sent anywhere?
No, the whole count runs in your browser.