PassForge

Generate strong passwords and memorable passphrases, entirely on your device — with a strength meter and crack-time estimate.

Passphrases and passwords reach strength differently. A random password's entropy is the log of the character set raised to the length; a passphrase's is the log of the wordlist size raised to the number of words. Six words from a 7,776-word list gives about 77 bits, which is stronger than most passwords people actually choose and far easier to retype.

Crack-time estimates are useful as a comparison rather than a prediction, since the real number depends entirely on how the target site stores the hash. What is reliable is the direction: length dominates, and substituting symbols for letters adds almost nothing.