Password Strength Checker
Get a real entropy score and estimated crack time for any password, with pattern and common-password detection — computed entirely offline.
How to use Password Strength Checker
- Use these example values as a starting point: Type a password to analyze.
- Set the inputs and options shown here: Password.
- This tool has no separate run button; its results update as you add or change the input.
- Review the result or preview on the page and confirm it matches your input before using or sharing it.
How is password strength calculated?
Entropy measures how many guesses an attacker would need on average, based on the character pool used (lowercase, uppercase, digits, symbols) raised to the power of the password's length. It's a reasonable first-order estimate, so this tool also checks for common weaknesses that entropy math alone misses — dictionary words, keyboard patterns, and repeated characters.
Why does a long password with only lowercase letters still score well?
Because length dominates entropy. A 20-character lowercase phrase can be harder to brute-force than an 8-character password with symbols, even though it looks "simpler."
Does this check against real-world breach databases?
No — doing that safely requires sending the password (or a hash of it) to an external service, which this tool deliberately avoids. Instead it checks against a local list of extremely common passwords and patterns.