Password Strength Checker
Assess password strength with entropy and crack-time estimates.
What is Strength Check?
A strength meter that estimates entropy from character variety and length, flags common passwords and patterns, and estimates time-to-crack.
How it works
Entropy is computed from the character-pool size and length; common-password and pattern checks add feedback; crack time assumes an optimistic online attack rate.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Testing a candidate password
Paste a password and get a strength score with feedback on length, variety, and common-pattern penalties.
Common mistakes
Complexity over length
Length beats character variety in practice — a long passphrase outranks a short symbol-studded password.
Frequently asked questions
Does it check against breached-password lists?
It flags common words and patterns locally; it does not query breach databases, so your password never leaves the browser.
What makes a password strong?
Length first, then randomness. Randomness matters more than forced complexity rules.