Estimate how strong a password is and how long it might take to crack.
Checked entirely in your browser — your password is never sent or stored.
How do you check how strong a password is?
Strength is estimated from entropy ≈ length × log2(pool size), where the pool grows with each character type used, plus a rough crack time assuming a fast offline attacker. Strength comes mainly from length and unpredictability, so avoid names, dates and common words. A 12-character password mixing cases, numbers and symbols typically rates "strong"; a short dictionary word rates "very weak".
Understanding your result
Strength comes mainly from length and unpredictability. Avoid names, dates and common words even when they look complex.
Formula and method
Entropy ≈ length × log2(pool size), where the pool grows with each character type used. Crack time assumes a fast offline attacker; treat it as a guide, not a guarantee.
Assumptions and limitations
The crack-time figure is a rough estimate assuming a fast offline attacker and should be treated as a guide, not a guarantee. Real safety also depends on whether the password has leaked or reuses a common pattern, which entropy alone cannot detect. The tool estimates strength from length and character variety; it does not check breach databases.
Worked example
A 12-character password mixing cases, numbers and symbols typically reaches a “strong” rating, while a short dictionary word rates “very weak”.
How to use this tool
- Type or paste the password.
- The strength updates instantly.
Common mistakes to avoid
- Assuming swapping letters for look-alike symbols (p@ssw0rd) makes a weak password strong.
About the Password Strength Checker
Test how resistant a password is to guessing. This tool estimates entropy and a rough crack time based on length and character variety.
Who should use this tool
For anyone auditing their own passwords before trusting them: individuals reviewing accounts, people learning what makes a password strong, and cautious users comparing candidate passwords. If you want a quick read on entropy and a rough crack-time estimate to guide your choice, this checker is built for that.
Benefits
- Estimates entropy from length and character variety
- Gives a rough crack-time guide to compare passwords
- Highlights that length matters most for strength
- Analyses your password locally, without sending it anywhere
Practical use cases
- Checking a new password before you commit to it
- Comparing two candidate passwords for strength
- Learning how length affects resistance to guessing
- Auditing an old password you still use
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Frequently asked questions
Is my password sent anywhere?
No. The check runs entirely in your browser and nothing is transmitted or logged.
How reliable is the crack-time estimate?
Treat it as a guide rather than a promise. It assumes a fast offline attacker and calculates from entropy, but it cannot know if your password has been leaked, follows a predictable pattern, or reuses a common word. A high estimate on a breached password offers little real protection, so context matters.
What matters most for a strong password?
Length and unpredictability count for the most. A longer password dramatically increases the possibilities an attacker must try, while mixing character types adds further variety. Just as important, avoid names, dates and dictionary words even when disguised, because attackers test those patterns first regardless of how complex they look.