Random String Generator
Generate random strings with various customization options using this free online tool.
Random String Generator
Generate random strings with various customization options using this free online tool.
About random string generation
Charset and pattern modes
Charset mode combines selected lowercase, uppercase, digit, and symbol sets with optional presets. Pattern mode lets each token control the output shape, including X for A-Z, a for a-z, L for any letter, 9 for digits, H for hex, the asterisk token for any supported character, backslash escapes, and {N} repeats.
FAQ
Common questions and answers about this topic.
What character sets are available?
You can choose from letters (uppercase and lowercase), numbers, symbols, or define custom character sets to match your specific needs.
Can I use this for passwords?
It generates random strings, but for security-critical passwords consider using a dedicated password manager that provides additional entropy and secure storage.
Can I control the string length?
Yes, you can specify any length you need and generate multiple strings at once.
Is my data sent to any server?
No, random string generation happens entirely in your browser. All strings are created locally with JavaScript — nothing is sent to any server.
What does entropy (in bits) mean?
Entropy measures unpredictability. The bits value is calculated as length × log2(charset size); higher means harder to brute force. NIST 800-63B suggests at least 60 bits for typical accounts, and 80+ bits for high-security use.
How do I use Pattern mode?
In Pattern mode each token represents a character class — X (A-Z), a (a-z), L (any letter), 9 (digit), H (hex 0-9 a-f), * (any letter/digit/symbol). Use \\<char> to escape, and {N} to repeat the previous token N times (e.g. H{8}-H{4} produces an 8-hex prefix followed by 4-hex).