How it works
How password strength analysis works
Use this free password strength analyzer to test how secure your passwords really are. Unlike basic checkers that only count character types, this tool uses the zxcvbn library to detect spatial keyboard patterns like qwerty, calendar dates like 1998, and common l33tspeak substitutions like @ for a.
The analyzer calculates cryptographic entropy in bits and estimates crack times against real-world attack scenarios. An online throttled API attack at 100 guesses per hour will take exponentially longer than an offline fast hash attack using an RTX 4090 GPU processing 160 billion MD5 hashes per second.
Every calculation runs entirely in your browser using the Web Crypto API. Your password is never transmitted over the network, logged, or stored. You can disconnect from Wi-Fi and the tool will still work perfectly.
This tool also checks your password against a curated local list of common passwords, simulates enterprise compliance policies like NIST 800-63B and PCI-DSS, and provides one-click hardening suggestions to transform weak passwords into stronger ones.