What Is a Password Strength Checker?
A password strength checker evaluates how resistant a password is to cracking attempts. It analyzes factors like length, character diversity, common patterns, and dictionary words to produce a strength score. This tool runs entirely in your browser—your password is never transmitted over the network.
How to Use This Password Strength Checker
- Type or paste a password into the input field.
- View the real-time strength rating and feedback on what makes the password strong or weak.
- Follow the suggestions to improve your password until it reaches a strong or very strong rating.
Key Concepts
Password strength is primarily determined by entropy—the number of possible combinations an attacker must try. Longer passwords with mixed character types (uppercase, lowercase, digits, symbols) have exponentially more combinations. However, common substitutions (like “@” for “a”) and dictionary words reduce effective entropy because attackers test these patterns first. A truly strong password is at least 12 characters long and avoids predictable sequences.
Frequently Asked Questions
Is my password sent to any server?
No. This tool performs all analysis locally in your browser using JavaScript. Your password never leaves your device, ensuring complete privacy. You can verify this by disconnecting from the internet and confirming the tool still works.
What makes a password weak?
Common weaknesses include short length (under 8 characters), dictionary words, sequential characters (abc, 123), keyboard patterns (qwerty), personal information (names, birthdays), and simple character substitutions like “p@ssw0rd.”
Should I use a passphrase instead?
Yes. A passphrase of four or more random, unrelated words (e.g., “correct horse battery staple”) is both strong and memorable. The length provides high entropy while the randomness defeats dictionary attacks. Combine it with a number or symbol for additional security.