Password Strength Checker
Check how strong your password is with a visual strength meter, criteria checklist, and estimated crack time. Everything runs locally in your browser.
How It Works
Type a password to get instant feedback on its strength:
- Strength meter — A color-coded bar from Weak (red) to Very Strong (green) based on length and character variety.
- Crack time estimate — How long a brute-force attack would take at 10 billion guesses per second.
- Criteria checklist — Shows which security criteria your password meets: minimum length, uppercase, lowercase, numbers, and special characters.
All analysis runs locally in your browser — your password is never sent to any server.
Frequently Asked Questions
Is my password sent to a server?
No. All password analysis happens entirely in your browser using JavaScript. Your password never leaves your device and is not stored or transmitted anywhere.
How is the strength score calculated?
The score is based on password length, character variety (uppercase, lowercase, numbers, special characters), and the combination of these factors. Longer passwords with more character types receive higher scores.
How is the crack time estimated?
The estimate assumes a brute-force attack at 10 billion guesses per second (a realistic rate for modern GPUs). It calculates the total possible combinations based on the character pool size and password length, then estimates the average time to find a match.
What makes a strong password?
A strong password is at least 12 characters long and includes a mix of uppercase letters, lowercase letters, numbers, and special characters. Avoid common words, personal information, and reusing passwords across sites.
Why does a longer password matter more than complexity?
Each additional character exponentially increases the number of possible combinations. A 16-character lowercase password has more combinations than an 8-character password using all character types.