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Password Strength

Check your password strength instantly. Entropy analysis, crack time estimation and security tips. 100% free and offline.

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Password Strength Checker — How Strong Is Your Password?

The Password Strength Checker is a free online tool that analyzes the security of your passwords in real time and provides a detailed strength assessment. As you type, the tool evaluates your password against multiple security criteria and displays a strength meter ranging from Very Weak to Very Strong, along with specific feedback on how to improve it. All analysis runs entirely in your browser — your password is never transmitted to any server.

The checker evaluates passwords based on length (minimum 8 characters recommended, 12+ for strong), character diversity (uppercase, lowercase, numbers, special characters), entropy (randomness and unpredictability), common patterns (keyboard sequences like qwerty, repeated characters, dictionary words), and known breaches (optional check against the Have I Been Pwned database using a k-anonymity protocol that never reveals your full password). The estimated crack time is displayed using realistic brute-force scenarios.

Individual users check passwords before creating accounts on important services. IT administrators verify that password policies produce adequately strong passwords. Security trainers demonstrate why certain password patterns are weak during awareness sessions. Developers test password validation logic in their applications. Compliance officers verify that organization passwords meet regulatory requirements (PCI DSS, HIPAA, SOC 2). The tool educates users about password security while protecting their privacy through client-side-only analysis.

Password Strength Checker is part of the facilita.tools security toolkit. Available in Portuguese, English, and Spanish, optimized for desktop and mobile browsers.

Frequently Asked Questions

Is my password sent to any server?
No. The entire analysis runs 100% in your browser using JavaScript. Your password never leaves your device — no API calls, no logging, no server requests.
What does entropy mean?
Entropy measures how unpredictable a password is, expressed in bits. A password using only lowercase letters has less entropy than one mixing uppercase, numbers, and symbols. Higher entropy means exponentially more guesses are needed to crack it.
How is crack time estimated?
We assume an attacker using a modern GPU cluster performing 10 billion guesses per second. The estimated time represents the average case (half the total keyspace). Real-world crack time may vary based on the attack method used.