Random Alphanumeric String Generator
Generates a random 12-character string using only letters and digits — no symbols — for placeholder IDs or test data that must avoid special characters, drawn independently character by character from a 62-character alphabet using the browser's cryptographic source.
What this generator does
Produces a random 12-character string of letters and digits, for filling identifier fields, reference codes and test inputs where the exact format does not matter.
How to use this tool
- Press generate for a random alphanumeric string.
Worked examples
- Format
- cPXcWpdpqeQW and RzYXu9Qtsq3r — two draws; the first happens to contain no digit at all
- Alphabet
- A–Z, a–z and 0–9
Common use cases
- Placeholder IDs that must avoid symbols
- Testing alphanumeric-only input fields
- Sample data for documentation
How this generator works
Twelve characters are drawn independently from a fixed 62-character set — upper-case letters, lower-case letters and digits — using the browser's cryptographic source, each by a draw that redraws rather than reducing a random byte to 62 values — the usual shortcut, which would make A to H come up 5 times in 256 against 4 for the rest. A 62-character set gives just under six bits a character, so a twelve-character string carries about 71 bits. The length and the character set are fixed; there is nothing to configure.
Limitations and good to know
- Not intended as a credential. The password and API key generators exist for that and are excluded from advertising for the same reason.
- Always 12 characters from all 62 letters and digits; there is no control for the length, the case or the character set.
- Similar-looking characters are all included. If the string will be read aloud or typed from a screen, 0 and O, 1 and l are where the mistakes happen.
- No structure is imposed, so a result may contain no digits at all — which fails the rules some systems impose on passwords.