Password Strength Checker
Check strength
Generate a strong password
Generated password
What makes a password strong?
Password strength comes primarily from length and unpredictability: longer passwords with a mix of uppercase, lowercase, numbers, and symbols are exponentially harder to guess or brute-force than short ones, even if the short one looks complex. Predictable patterns — like sequential characters, repeated characters, or common words — weaken a password regardless of length.
When would I use this?
- Checking whether a password you're about to use meets a reasonable strength bar before setting it.
- Generating a strong, random password for a new account.
- Understanding exactly which strength criteria a password is missing.
How it works
Strength scoring runs entirely in your browser using JavaScript — your password is never transmitted, logged, or stored. Generated passwords use the Web Crypto API's cryptographically secure random number generator.
Frequently asked questions
No, the strength check runs entirely in your browser using JavaScript. Your password is never transmitted, logged, or stored anywhere — not even temporarily.
Length, the variety of character types used (lowercase, uppercase, numbers, symbols), and whether the password matches common weak patterns like sequential characters or repeated characters.
Using your browser's cryptographically secure random number generator (crypto.getRandomValues), from a character set you choose, ensuring strong, unpredictable results.
No, this tool only evaluates structural strength (length and complexity). It doesn't check against known breach databases, so avoid reusing passwords across sites regardless of their strength score.