Generators · Free Tool
Password Strength Checker
Check how strong a password really is — entropy estimate, character variety, and specific weaknesses like repeats or common patterns — entirely in your browser.
Everything above runs locally in your browser. The password you type is never sent anywhere, logged, or stored — not even in this page's own code.
About this tool
Type or paste a password and get an instant strength read: an entropy estimate in bits, a plain-English strength label from Very Weak to Very Strong, and a specific checklist of what's helping or hurting — length, character variety, repeated characters, sequential runs like "1234" or "abcd", and whether it matches a handful of the most commonly breached passwords.
Nothing you type is sent anywhere — the check runs entirely in JavaScript in your browser, the same privacy guarantee as this site's password generator. That matters here specifically, since a password-strength tool that phoned home would be a strange thing to trust with your actual password.
Common uses
- Check a new password meets a reasonable strength bar before using it on an important account
- See exactly which weakness (length, repetition, a common pattern) is dragging a password's score down
- Compare two candidate passwords or passphrases side by side before picking one
Frequently asked questions
Is my password sent to a server when I check it?
No. The entire check runs locally in your browser with JavaScript — the password you type is never transmitted, logged, or stored anywhere, even temporarily.
What does the entropy number in bits actually mean?
Entropy estimates how many guesses an attacker would need in the worst case, doubling with every added bit. As a rough guide, 40 bits is weak, 60 is reasonable for a low-value account, and 80+ bits is strong enough for anything sensitive when paired with a password manager.
Why did a long password still score as weak?
Length helps, but predictable structure hurts more than raw character count suggests — "aaaaaaaaaaaa" and "password123456" are both long yet trivially guessable. The checker specifically flags repeated characters, sequences, and known common passwords regardless of length.
Is my data uploaded to a server?
No. This tool runs entirely in your browser using JavaScript — nothing you type is transmitted, logged, or stored anywhere. You can even use it offline once the page has loaded.