Password Strength Checker: Test Passwords Privately
This Password Strength Checker uses zxcvbn to score passwords from 0 to 4 based on patterns such as dictionary words, common passwords, keyboard sequences, repeats, and l33t speak. Review estimated offline crack time, guess count, a breakdown of detected patterns, and suggestions for improving a password. The check runs locally in your browser, so the password is not sent to a server.
The Password Strength Checker uses zxcvbn to estimate how resistant a password may be to real-world guessing. It assigns a score from 0 to 4 and displays an estimated offline crack time, a guess count, a breakdown of detected patterns, and suggestions for improving the password. zxcvbn is described as the estimator behind Dropbox and 1Password.
The analysis looks for patterns including dictionary words, common passwords, keyboard patterns, l33t speak, repeated characters or patterns, and sequences. Instead of relying only on password length or character types, the checker shows which recognizable patterns zxcvbn found and provides feedback you can use when revising a password.
Passwords and other text are different from the structured data handled by many developer tools: a password is assessed for patterns that could make it easier to guess. The score, guess count, and estimated crack time offer different ways to review that assessment. The pattern breakdown and suggestions can help explain the result and guide a revised attempt.
The check runs entirely in your browser, so your password is processed on your device and is not sent to a server. The tool has no server dependency, so after the page has loaded, it can continue to work offline. This makes it useful when you want a browser-based assessment without sending the password to a third-party service.
Developers, DevOps engineers, and other users can use the checker to review a password, understand the patterns it contains, and consider suggestions before choosing a revised version. It runs in the browser, so there is no need to install a local tool for a routine check.
Step 1: Enter, paste, or drop a password into the checker to begin the analysis.
Step 2: Review the score from 0 to 4 to see the tool’s overall estimate of password strength.
Step 3: Check the estimated offline crack time, guess count, and pattern breakdown to understand what zxcvbn detected.
Step 4: Read the improvement suggestions, then try an updated password if you want to compare the results.
Step 5: Copy the result if you need to refer to the analysis elsewhere.
Use case: Check a password you are considering for a new account and review the suggestions before using it.
Use case: Understand why a password may be easier to guess by looking at detected dictionary words, keyboard patterns, repeats, or sequences.
Use case: Compare an original password with a revised version by reviewing their scores and estimates.
Use case: Complete a routine password-strength check in your browser without installing a local tool.
Use case: Use the checker on the machine available to you when you need a quick password assessment.
Use case: Avoid pasting a password into a third-party service: the checker processes it locally, and it never leaves your browser.