Password Generator

Generate cryptographically secure random passwords, or analyze the strength of an existing one — entirely in the browser.

Generate mode

Length — slider from 4 to 128 characters
Charset — any combination of uppercase A–Z, lowercase a–z, digits 0–9, and symbols !@#$%^&*()-_=+[]{}|;:,.<>?
Count — generate 1 to 20 passwords at once

Passwords are generated using crypto.getRandomValues, the Web Crypto API's cryptographically secure random number generator. No data is sent to a server.

Check mode

Paste or type any password to get an instant strength analysis:

Strength meter — five-segment bar from Very Weak (red) to Very Strong (green)
Entropy — bits of entropy based on the observed character classes and length
Charset — which character classes are present (A-Z, a-z, 0-9, symbols)
Estimated crack time — how long a brute-force attack would take at 10 billion guesses/second (offline fast-hash scenario), reported as an average-case estimate

The checked password is intentionally never written to the URL or sent anywhere.

Entropy model

Entropy = length × log₂(charsetSize), where charsetSize is the sum of each present character class: 26 (uppercase) + 26 (lowercase) + 10 (digits) + 32 (symbols). This is a lower-bound estimate — it assumes a random draw from the observed classes and does not account for dictionary words, patterns, or repeated characters.

Strength	Entropy range
Very Weak	< 28 bits
Weak	28–35 bits
Fair	36–59 bits
Strong	60–127 bits
Very Strong	≥ 128 bits

Permalink

In Generate mode, the URL encodes your current settings (length, charset options, count) so you can share or bookmark a configuration. Passwords themselves are never stored in the URL.

In Check mode, the URL records ?mode=check so the page reloads into check mode, but the input is always empty.