We've all seen those strength meters that show "Weak" or "Strong" as you type a password. But what's actually happening under the hood? How does a computer decide if your password is secure?
Our Password Strength Checker analyzes every aspect of your password - not just length, but character diversity, common patterns, and estimated crack time. It checks six criteria: length (both minimum and recommended), uppercase letters, lowercase letters, numbers, and symbols. The more criteria you satisfy, the higher your score.
The Math Behind Password Strength
Password strength comes down to entropy - a measure of unpredictability. A password like "password123" has very low entropy because it follows predictable patterns. A password like "kX9#mP2$vL7@nQ5" has high entropy because it's long, uses all character types, and follows no discernible pattern.
Your character space (the pool of possible characters per position) is calculated based on which character types you use. If you use all four types (upper, lower, numbers, symbols), each position has 94+ possibilities. For a 12-character password, that's 94^12 possible combinations - a number so large it takes centuries to brute force.
Privacy Guarantee
Your password is never sent anywhere. All analysis happens locally in your browser. We don't log, store, or transmit anything you type.
What Makes a Strong Password?
- At least 12 characters - every character adds exponential security
- Mix of character types - uppercase, lowercase, numbers, symbols
- No common patterns - avoid "password", "123456", "qwerty"
- No personal info - avoid names, birthdays, addresses
Remember: the best password is one you don't have to remember. Use a password manager to generate and store unique passwords for every site.