Password Strength Checker
Test your password with real-time entropy analysis, crack time estimates, and actionable improvement tips.
How It Works
Entropy Analysis
Calculates the information entropy of your password based on character pool size and length.
Crack Time Estimate
Estimates how long a brute-force attack would take at 10 billion guesses per second.
Pattern Detection
Identifies common patterns like dictionary words, keyboard walks, repeated characters, and sequences.
100% Client-Side
Your password never leaves your browser. No network requests, no logging, no tracking.
FAQ
Is my password uploaded to a server?
No. Everything runs in your browser using JavaScript. Your password is never transmitted anywhere. You can verify by checking the network tab in your browser's developer tools.
What is password entropy?
Entropy measures the unpredictability of a password in bits. A password with 80+ bits of entropy
is considered very strong. The formula is: entropy = log2(pool_size^length).
How is crack time calculated?
We estimate based on 10 billion guesses per second (GPU-accelerated brute force). Real-world attacks may be faster or slower depending on the hashing algorithm used.
Is a long password always better?
Length is the strongest factor, yes. A 16-character password from a large character set is exponentially harder to crack than an 8-character one. But avoid using common phrases or patterns even in long passwords.