Password Strength & Crack Time Checker
Test password entropy, estimated AI/GPU brute force crack time, character diversity, and common dictionary weaknesses. 100% Client-side safe.
Your password never leaves your browser. Evaluated 100% locally in JavaScript.
340 Million Years
VERY STRONG (100/100)Complete Guide to Password Entropy & Cyber Threat Resistance
In cybersecurity, password entropy is the mathematical measure of unpredictability and randomness contained within an authentication credential. High entropy is the single most important barrier preventing automated botnets, credential stuffers, and high-performance GPU hash-cracking clusters (running Hashcat or John the Ripper) from compromising accounts.
The Information Entropy Formula
Shannon Entropy for passwords is calculated in bits as:
- L = Number of characters (Length).
- R = Size of the character pool (Numbers = 10, Lowercase = 26, Uppercase = 26, Symbols = 32). Total full ASCII pool = 94.
- Entropy Benchmark: > 65 bits is resistant to offline GPU attacks; > 80 bits is considered mathematically unbreakable for modern hardware.
NIST Digital Identity Guidelines (SP 800-63B)
- Length Over Complexity: A 16-character four-word passphrase (e.g.,
correct-horse-battery-staple) is exponentially harder to crack than an 8-character string likeP@55w0rd!. - Ban Common Dictionary Words: Attackers use rainbow tables and wordlists containing over 10 billion leaked passwords.
- Enable MFA Everywhere: Multi-Factor Authentication prevents 99.9% of automated account takeover attempts.
Frequently Asked Questions (FAQs)
Is it safe to test my real password on this website?
Yes, 100%. This tool operates entirely inside your local web browser using client-side JavaScript. No password data is ever transmitted over the network, stored in cookies, or recorded on web servers. You can even disconnect your internet connection and the tool will continue working perfectly.
How do GPU clusters crack passwords so fast?
Modern password-cracking rigs equipped with multiple NVIDIA RTX 4090 GPUs can compute over 100 billion NTLM/MD5 hash guesses per second. Short 8-character passwords with letters and numbers can be exhausted in less than 30 minutes, whereas 14+ character combinations require astronomical compute times spanning millions of years.
What is the best way to manage unique strong passwords?
Use a certified zero-knowledge password manager (like Bitwarden, 1Password, or KeePass) to generate and store 16+ character pseudorandom passwords for every account. You only need to memorize one high-entropy master passphrase.