What does the entropy number mean?

How much genuine unpredictability the password holds. Under 60 bits is weak, 80 is solid, over 100 is beyond brute force. It is a far better guide than a coloured strength bar.

Are these passwords really random?

Yes — they use your browser’s cryptographic random generator, not the ordinary one. Nothing is sent anywhere or stored.

Random characters or a passphrase?

A passphrase for anything you must type by hand or remember: four random words carry similar entropy to a short jumble and are far easier to enter. Random characters for anything living in a password manager.

Password Generator

Cryptographically random strings or passphrases, with real entropy shown in bits.

Runs in your browser — nothing uploaded

Report a problem

How to use Password Generator

Choose random characters or a passphrase of real words.
Set the length and which character types to include.
Read the entropy in bits, then copy.

How long is long enough

Time to crack an offline hash at a trillion guesses a second — the rate a well-funded attacker with modern hardware reaches.

Length	Letters only	Letters, digits, symbols
8 characters	minutes	hours
10 characters	days	months
12 characters	decades	thousands of years
16 characters	far beyond a lifetime	far beyond a lifetime
4 random words	centuries	—

Length beats complexity. Adding one character multiplies the work more than swapping an o for a 0 ever does.

None of this protects a password that has been reused somewhere that leaked — that attack needs no guessing at all.

Questions

What does the entropy number mean?: How much genuine unpredictability the password holds. Under 60 bits is weak, 80 is solid, over 100 is beyond brute force. It is a far better guide than a coloured strength bar.
Are these passwords really random?: Yes — they use your browser’s cryptographic random generator, not the ordinary one. Nothing is sent anywhere or stored.
Random characters or a passphrase?: A passphrase for anything you must type by hand or remember: four random words carry similar entropy to a short jumble and are far easier to enter. Random characters for anything living in a password manager.