Password Generator
Cryptographically random passwords with an honest entropy readout.
Runs in your browserOptions
Character set size: 87· Entropy: 129 bit ·Excellent
About this tool
Generate passwords from your browser's cryptographic random source, avoiding the predictable output that Math.random produces. You choose the length and which character sets to include, and the tool reports the actual entropy in bits alongside a plain explanation of what that number means, rather than a vague strength label.
How to use it
- 1Set the length and tick the character sets you want.
- 2Read the entropy figure to see how strong the result really is.
- 3Generate and copy — or tick a few extra options and let it regenerate automatically.
Frequently asked questions
What makes the randomness trustworthy?
Values come from crypto.getRandomValues, the browser's cryptographic random source, which is the same one used for encryption keys. On top of that, characters are selected by rejection sampling: a value that would bias the distribution towards the start of the character set is discarded and redrawn.
How much entropy do I need?
About 60 bits stops an online attacker guessing within any realistic timeframe. 90 bits is beyond anything achievable with current hardware, and 128 bits is the standard for long-lived secrets. A 20-character password using all four character sets reaches roughly 128 bits.
Why does it promise each character set is used?
If you tick the symbols box and the generator happens to produce a letters-only password, the password is weaker than the entropy figure suggests. So one character is drawn from each selected set first, then the rest fill up, and finally the whole thing is shuffled so the position is not predictable.