Password Strength Checker - Free Password Tester & Quantum Strength Test
Test your password strength for free with our advanced password security analyzer. Upgrade to see estimated crack times against quantum computing attacks using Grover's algorithm. All password checks run in your browser - we never see your password. Check password strength, entropy, and resistance to hacking attacks instantly.
🔮 Premium: Quantum Analysis + Password Generator + Breach Check
Get detailed quantum resistance estimates, generate quantum-resistant passwords from memorable phrases, AND check if your password appears in 800+ million known breaches.
Theoretical estimates using Grover's algorithm
Turn phrases into quantum-resistant passwords
Check 800M+ breached passwords (HIBP)
All included for just $1.00 - pay once, use all three tools!
How Our Password Strength Checker Works
Our password checker uses advanced algorithms to analyze password security through three key security features:
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🔒 100% Private & Secure
Your password never leaves your browser. All password strength analysis runs client-side using JavaScript in your web browser. We never transmit, store, or log your password to any server. This ensures complete privacy and security when checking password strength.
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🧮 Smart Password Analysis
Uses the industry-standard zxcvbn algorithm (developed by Dropbox) to detect weak patterns, common passwords, dictionary words, and calculate password entropy. Our password tester provides real-time feedback on password strength including crack time estimates against modern GPU attacks.
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⚛️ Quantum Resistance Analysis
Premium feature provides theoretical quantum resistance estimates using Grover's algorithm modeling for educational and future-proofing purposes. Learn how your password would theoretically fare against quantum computing attacks.
⚠️ Note: Large-scale quantum computers don't yet exist. These are theoretical educational estimates for future-proofing research, not current threats.
Frequently Asked Questions About Password Strength Testing
Common questions about password security, strength checking, and quantum resistance analysis.
Is my password strong enough?
A strong password should have at least 12 characters, include a mix of uppercase, lowercase, numbers, and symbols, and avoid common words or patterns. Our free checker analyzes your password using the zxcvbn algorithm (developed by Dropbox) to detect weak patterns. For quantum resistance, aim for 80+ bits of entropy.
How do hackers crack passwords?
Hackers use several methods: (1) Dictionary attacks - trying common words and passwords, (2) Brute force - trying every possible combination using powerful GPUs, (3) Rainbow tables - pre-computed hashes of common passwords, and (4) Credential stuffing - using passwords leaked from other breaches. Modern GPUs can try billions of password combinations per second.
What makes a password theoretically quantum resistant? (Educational)
Note: These are theoretical estimates for educational purposes. Quantum computers using Grover's algorithm could theoretically crack passwords twice as fast (effectively halving the bits of security). A password with 80 bits of classical security would theoretically become 40 bits against quantum attacks. To be theoretically quantum-resistant, you would need at least 80 bits of quantum security, which means 160+ bits classically - typically requiring 25+ random characters or a long passphrase (6+ random words). Large-scale quantum computers capable of this do not yet exist.
How long would it take to crack my password?
Crack time depends on password complexity and the attacker's hardware. A modern GPU can try ~10 billion passwords/second. A simple 8-character password with only letters and numbers can be cracked in minutes. However, a 16-character password with mixed case, numbers, and symbols would take thousands of years. Our tool calculates both classical (GPU) crack time estimates and theoretical quantum (Grover's algorithm) estimates for educational purposes.
Is this password checker safe to use?
Yes! Your password never leaves your browser. All analysis runs client-side using JavaScript - we never transmit, store, or log your password. You can even disconnect from the internet and the tool will still work. For extra peace of mind, you can inspect the source code or test with a similar (but not identical) password.
What is password entropy?
Entropy measures password randomness in bits. Each bit doubles the number of possible combinations. For example, 40 bits = 1 trillion possibilities, 60 bits = 1 quintillion. Higher entropy = stronger password. Aim for 60+ bits for good security, 80+ for excellent security, and 100+ for quantum resistance.