Password Strength Checker
Analyze password strength in real-time with entropy calculation, crack time estimates, and improvement recommendations.
About Password Strength Checker
Our free online Password Strength Checker analyzes the security of your passwords in real-time. It evaluates multiple factors including length, character diversity, entropy, and common password patterns to give you a comprehensive assessment.
Password entropy measures the unpredictability of a password in bits. Higher entropy means the password is harder to guess through brute force attacks. Our tool calculates entropy based on the character pool size and password length.
The tool detects common weak patterns such as sequential characters (abc, 123), repeated characters (aaa), dates, and common passwords like "password123". It also provides specific recommendations to improve your password security.
All analysis happens entirely in your browser using JavaScript, ensuring your password never leaves your device. Use this tool to test password candidates and understand what makes a strong, secure password.
Features
Real-Time Analysis
Instantly evaluate password strength as you type with live feedback.
Entropy Calculation
Calculate password entropy in bits to measure unpredictability.
Crack Time Estimate
Estimate how long it would take to crack your password via brute force.
Pattern Detection
Detect sequences, repeats, dates, and common password patterns.
Smart Recommendations
Get actionable suggestions to improve your password security.
Privacy First
All analysis happens in your browser. Your password never leaves your device.
How to Use
Enter Your Password
Type or paste the password you want to analyze into the input field.
Review Strength Meter
Check the strength meter and score to see the overall security level.
Check Analysis Details
Review length, character diversity, entropy bits, and crack time estimate.
Apply Recommendations
Follow the suggestions to improve your password strength and security.
Frequently Asked Questions
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 symbols. It should not contain common words, patterns, or personal information.
What is password entropy?
Entropy measures the unpredictability of a password in bits. It is calculated based on the size of the character pool and the password length. Higher entropy means a more secure password that is harder to crack.
How is crack time estimated?
Crack time is estimated by dividing the total number of possible combinations (based on entropy) by the assumed cracking speed (1 trillion guesses per second). This provides a theoretical estimate, not an absolute guarantee.
Is my password safe when using this tool?
Yes, all analysis happens entirely in your browser. Your password is never sent to any server or stored anywhere. You can use this tool even offline after the initial page load.
How many bits of entropy do I need?
Security experts recommend at least 60 bits for general use, 80 bits for sensitive accounts, and 100+ bits for highly critical systems. This tool rates Very Strong at 80+ bits of entropy.
Is this tool free?
Yes, it is completely free to use with no registration, sign-up, or limits. Analyze as many passwords as you need.