Free Password Strength Checker Tool Online
Test password strength with entropy analysis, crack time estimates, and security tips, all processed locally in your browser.
IN: Password · OUT: Strength score & criteria · RUNS: 100% in your browser
This check runs entirely in your browser and never transmits or stores what you type. Estimates are illustrative, not a guarantee — real-world crack times depend on the attacker's method and hardware.
Frequently asked questions
How is the strength score calculated?+
It estimates entropy in bits based on password length and which character sets are used (lowercase, uppercase, digits, symbols) — more length and more character variety both increase the total number of possible combinations an attacker would need to try.
How accurate is the estimated crack time?+
It's a rough illustrative estimate assuming a fixed offline guessing rate, meant to give a sense of relative strength, not a precise real-world prediction — actual crack time depends heavily on the specific attack method, hashing algorithm used to store the password, and attacker's hardware.
Why does a long password with only lowercase letters still get a lower score than a shorter mixed-case one?+
Entropy depends on both length and pool size (how many possible characters at each position) — a small character set needs significantly more length to match the same entropy as a mixed-case, digit, and symbol combination.
Does this check if my password has been in a data breach?+
No, this tool only analyzes the password's structural strength (length and character variety) locally in your browser. It does not check breach databases, since doing so safely would require sending data externally, which this tool deliberately avoids.
Is my password sent anywhere while I type?+
No, absolutely not — the entire analysis runs locally in your browser using JavaScript, and the password is never transmitted, logged, or stored anywhere, including by this site.
Should I trust a password just because it scores 'Very strong' here?+
A high score indicates strong resistance to brute-force guessing, but overall account security also depends on not reusing passwords across sites and enabling two-factor authentication where available.