How do you pick a random letter?
Give each of the 26 letters of the alphabet an equal chance and draw one. This generator does that up to 200 times in a row, in uppercase, lowercase or a random mix, and returns the letters as a single string. The draws use your browser's cryptographically secure random source, so there's no pattern to the sequence.
Getting letters
- Choose how many Letters you want, from 1 to 200 (default 10).
- Choose a Case: Mixed (the default), Uppercase or Lowercase.
- Click Generate, and click again for a fresh set.
Some results from the tool:
| Settings | Example output |
|---|---|
| 10 letters, mixed | ewfqkBHkAq |
| 10 letters, mixed | CVNIDMcdTs |
| 5 letters, uppercase | BDYCU |
| 5 letters, lowercase | rbjkx |
Notice rbjkx: five letters and no vowel. That's not a glitch. With five vowels out of 26, the chance a 5-letter random string has none of a, e, i, o, u is about 34%.
Random letters versus English letters
People tend to expect random letters to look like scrambled English. They don't, because the tool draws from a flat distribution. In ordinary text you rarely see Q, X or Z; here each turns up 1 time in 26, exactly as often as E. For some uses that's what you want, and for others it's a problem:
- Fair for games. In a category game where everyone must name a city, animal and food starting with the chosen letter, a flat draw is fair in the sense that every letter has the same chance. If X and Q make rounds too hard, agree up front to re-roll them.
- Bad for word puzzles. If you want random tiles that can form words, uniform letters give too few vowels. Weighted tile sets (as in Scrabble-style games) exist for that reason.
Why mixed case is built the way it is
In Mixed mode the code decides the case first (a fair coin), then the letter. Because both alphabets have 26 letters, every one of the 52 characters ends up with the same 1 in 52 chance. Expect roughly half uppercase: in 10 mixed letters, exactly five capitals happens about a quarter of the time, and all ten capitals only about once in 1,024 runs.
Each choice goes through the site's shared random helper, which takes 32-bit values from crypto.getRandomValues and uses rejection sampling to map them to a letter without the remainder bias of a plain %. Nothing is sent to a server.
Uses that suit random letters
- Classroom alphabet drills. Call out random letters for children to write, find on a keyboard or match to a sound. Uppercase mode keeps it simple for early readers.
- Typing practice. A string of random lowercase letters takes away the word shapes your fingers have memorised, which makes it a decent finger-placement drill.
- Starting letters for games and writing prompts. Generate one letter per round.
- Test data. Random initials, short codes, or field values that must be letters only, such as a two-letter state-style code for a form validator.
- Shuffled alphabets. For a substitution-cipher key you need all 26 letters once each, which random draws won't give you; put A to Z on separate lines and use the text lines shuffler instead.
What it isn't good for
Random letters make a poor password. Ten lowercase letters hold about 47 bits of entropy (26¹⁰ possibilities), and ten mixed-case letters about 57 bits, both short of what you want for an account. The password generator adds digits and symbols and goes up to 64 characters. If you need letters and digits together, the random alphanumeric generator draws from all 62.
Want to see what the letters are underneath? The text to ASCII converter shows each one's character code: uppercase A to Z are 65 to 90, and lowercase a to z are 97 to 122, as defined in the original ASCII standard (RFC 20). To flip the case of a generated string afterwards, use the case converter.
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