Free · Private · Client-side
Password Strength Checker
Test how secure your password is. Get instant feedback on entropy, estimated crack time, and suggestions for improvement — analyzed entirely in your browser.
Generated values never leave this device.Checked locally — your password never leaves your browser and is never sent to any server.
Type a password above to see its estimated entropy, strength rating, and crack time.
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Your privacy
This tool runs entirely in your browser. Your password is never sent to any server, stored, or logged. You can verify this by disconnecting from the internet and testing — it will still work.
Need a strong password?
Generate a cryptographically secure password with our generator:
Password best practices
Do
- • Use 12+ characters minimum
- • Mix uppercase, lowercase, numbers, symbols
- • Use a unique password for each account
- • Consider using a passphrase
- • Use a password manager
Don't
- • Use personal info (names, birthdays)
- • Use common words or phrases
- • Use keyboard patterns (qwerty, 123456)
- • Reuse passwords across sites
- • Share passwords via email or text
How password strength is calculated
Password strength is calculated based on several factors:
- Entropy — a measure of randomness based on password length and character set diversity. Higher entropy = more combinations to guess.
- Character variety — using lowercase, uppercase, numbers, and symbols increases the possible combinations exponentially.
- Length — each additional character multiplies the total combinations by the charset size.
- Pattern detection — common patterns, repeated characters, and dictionary words make passwords easier to crack.