Password Strength Checker

About Password Strength Checker

A password strength checker estimates how hard a password would be to guess. Type a password to test its strength and it shows a rating, an entropy estimate in bits, and a checklist of what would make it stronger — length, uppercase and lowercase letters, numbers, and symbols. It's a quick way to sanity-check a password before you use it. Everything is calculated locally in your browser, so nothing is sent or stored.

Frequently asked questions

Is it safe to type my password into this checker?

Yes. The check runs entirely in your browser using JavaScript — your password is never sent over the network, logged, or stored anywhere.

How is password strength measured, and what are bits of entropy?

It estimates entropy: the password's length combined with how large a character set it draws from (lowercase, uppercase, digits, symbols). More length and more variety mean more bits — roughly log2(charset^length) — and a stronger rating.

What makes a strong password?

Length matters most. Aim for at least 12–16 characters mixing upper and lower case, numbers, and symbols — or use a long passphrase of several random words.

Does it check crack time or whether my password was breached?

No. It measures entropy, not crack-time estimates or breach lists. A long password built from a common word or pattern can score high here yet still be guessable, so avoid dictionary words and reuse.