Password Strength Meter
Estimate a password’s entropy in bits and get a strength rating and tips.
Rate a password by its entropy
A password’s real strength is roughly its entropy — how many guesses an attacker would need. This meter estimates that from the length and the character set you use, then rates it and points out what would help most.
A short mixed password can score fewer bits than a long lowercase passphrase, which is why length beats clever substitutions. The tool shows the bit estimate, a rating, and specific suggestions like adding length or a symbol.
Analysed privately
The password never leaves your browser — nothing is stored, logged, or uploaded — so you can safely test the ones you actually use.
Frequently Asked Questions
How is strength measured?
By estimating entropy: the length multiplied by the bits per character of the character set used. More length and more variety mean more bits and a stronger password.
Is my password sent anywhere?
No. It is analysed entirely in your browser and never stored, logged, or transmitted. You can type a real password safely.
What is a strong number of bits?
Below about 40 bits is weak, 60–80 is reasonable, and 100+ is strong. Length matters more than swapping a few symbols in.
Browse the full set of free, private, in-browser tools.