🔐 Password Strength Checker
Test your password strength with advanced security analysis. Get instant feedback on entropy, crack time, patterns, and improvement suggestions. 100% private - all checks happen in your browser.
🔒 Your password is never sent to any server. All analysis happens locally in your browser.
⏱️ Estimated Crack Time
📊 Character Composition
⚠️ Security Issues Detected
💡 Recommendations
✅ Strengths
What Is a Password Strength Checker?
A password strength checker is a security tool that analyzes passwords to determine how resistant they are to various cracking methods. It evaluates multiple factors including length, character diversity, entropy (randomness), common patterns, dictionary words, and whether the password appears in known data breach databases. The tool provides a strength score and detailed feedback to help users create more secure passwords.
Our password strength checker uses advanced algorithms to calculate entropy, estimate crack times under different attack scenarios, detect common patterns like keyboard sequences and repeated characters, and check against lists of commonly used passwords. Unlike basic checkers that only count character types, our tool provides comprehensive analysis including real-world crack time estimates based on current computing capabilities.
Privacy is paramount when checking password strength. Our tool performs all analysis locally in your browser using JavaScript - your password never leaves your device, is not transmitted to any server, and is not stored anywhere. This ensures complete confidentiality while still providing professional-grade security analysis that helps you understand and improve your password security.
How to Use This Tool
Enter Your Password
Type or paste the password you want to test into the input field. The analysis begins automatically as you type, providing real-time feedback.
Review the Strength Meter
Watch the visual strength meter that shows your password's overall security level from Very Weak to Very Strong, with color-coded feedback.
Check Detailed Analysis
Review the comprehensive breakdown including entropy score, crack time estimates, character composition, and detected patterns or weaknesses.
Read Security Issues
Pay attention to any warnings about common passwords, patterns, or weaknesses that make your password vulnerable to attacks.
Follow Recommendations
Implement the suggested improvements to strengthen your password. The tool provides specific, actionable advice based on your password's weaknesses.
Key Features
Real-Time Analysis
Instant feedback as you type with live strength meter, entropy calculation, and security warnings updating in real-time.
Entropy Calculation
Advanced entropy measurement in bits showing the true randomness and unpredictability of your password.
Crack Time Estimates
Realistic time estimates for both online and offline attacks based on current computing capabilities and attack methods.
Pattern Detection
Identifies keyboard patterns, sequences, repeated characters, common substitutions, and dictionary words that weaken passwords.
Common Password Check
Compares against databases of commonly used passwords and passwords from known data breaches.
100% Private
All analysis happens locally in your browser. Your password never leaves your device or gets stored anywhere.
Why Use This Tool?
Understand Real Password Security
Many people think adding a number and symbol makes a password secure, but that's not enough. Our tool shows you the reality - how long your password would actually take to crack, what patterns make it vulnerable, and why length matters more than complexity. Understanding these factors helps you create genuinely secure passwords instead of following outdated rules.
Protect Against Modern Attacks
Hackers use sophisticated tools that can try billions of password combinations per second, check against breach databases, and recognize common patterns. Our checker simulates these real-world attack methods to show you exactly how vulnerable your password is. This helps you stay ahead of evolving threats and create passwords that resist modern cracking techniques.
Get Actionable Improvement Tips
Instead of just saying "weak password," our tool explains exactly what's wrong and how to fix it. Whether it's adding length, removing patterns, avoiding dictionary words, or increasing character variety, you get specific recommendations that directly address your password's weaknesses. This educational approach helps you develop better password habits.
Maintain Complete Privacy
Testing passwords online can be risky if the tool sends your password to a server. Our checker eliminates this risk by performing all analysis locally in your browser using JavaScript. Your password never leaves your device, ensuring you can safely test even your most sensitive passwords without any privacy concerns.
Practical Examples
Example 1: Weak Password
Password123
Analysis:
- • Strength: Very Weak (20/100)
- • Entropy: 36 bits
- • Crack time: Instant (less than 1 second)
- • Issues: Common password, dictionary word, predictable pattern
- • Recommendation: Use at least 12 characters with mixed types
Example 2: Moderate Password
Tr0pic@lSun
Analysis:
- • Strength: Moderate (55/100)
- • Entropy: 52 bits
- • Crack time: 3 days (offline attack)
- • Issues: Dictionary words, common substitutions (0 for o, @ for a)
- • Recommendation: Add more length and avoid predictable substitutions
Example 3: Strong Password
9mK#pL2$vN8@qR5&wT
Analysis:
- • Strength: Very Strong (95/100)
- • Entropy: 118 bits
- • Crack time: Centuries (even with offline attack)
- • Strengths: Excellent length, high character variety, no patterns
- • Note: Consider using a password manager to remember this
Understanding Password Entropy
Password entropy is a measurement of how unpredictable and random a password is, expressed in bits. Higher entropy means more possible combinations, making the password exponentially harder to crack. Entropy is calculated based on the character set size (pool) and password length.
Entropy Formula:
Entropy (bits) = log₂(pool_size^length)
Entropy (bits) = length × log₂(pool_size)
Character Pool Sizes:
- • Lowercase only (a-z): 26 characters
- • + Uppercase (A-Z): 52 characters
- • + Numbers (0-9): 62 characters
- • + Symbols (!@#$...): 94+ characters
Entropy Strength Guidelines:
- • < 28 bits: Very Weak (crackable instantly)
- • 28-35 bits: Weak (crackable in seconds)
- • 36-59 bits: Moderate (crackable in hours to days)
- • 60-79 bits: Strong (crackable in years)
- • 80+ bits: Very Strong (crackable in centuries)
Tips & Best Practices
Prioritize Length Over Complexity
A 16-character password with only lowercase letters is stronger than an 8-character password with all character types. Length increases entropy exponentially, while adding character types only multiplies it. Aim for at least 12 characters, preferably 16 or more.
Use Passphrases for Memorability
Create memorable passwords using random words combined together, like "correct-horse-battery-staple". These are long, easy to remember, and have high entropy. Add numbers and symbols between words for extra security.
Avoid Personal Information
Never use names, birthdays, addresses, phone numbers, or other personal details that can be found on social media or public records. Attackers often try these first in targeted attacks.
Don't Reuse Passwords
Every account should have a unique password. If one site gets breached, attackers will try that password on other sites. Use a password manager to generate and store unique passwords for each account.
Avoid Common Substitutions
Replacing 'a' with '@', 'e' with '3', or 'o' with '0' doesn't fool modern cracking tools. These substitutions are well-known and programmed into password crackers. True randomness is more effective.
Enable Two-Factor Authentication
Even the strongest password can be compromised. Two-factor authentication adds a second layer of security, requiring both your password and a code from your phone or authenticator app.
Common Mistakes to Avoid
Using Dictionary Words
Passwords like "sunshine" or "football" are vulnerable to dictionary attacks where crackers try every word in the dictionary. Even combining two words like "sunshineblue" is weak. If you use words, combine at least 4-5 random words with separators.
Keyboard Patterns
Patterns like "qwerty", "asdfgh", "12345", or "qazwsx" are among the first things attackers try. These patterns are easy to type but equally easy to crack. Avoid any sequence that follows keyboard layout or number order.
Repeated Characters
Using repeated characters like "aaa" or "111" or patterns like "ababab" significantly reduces entropy. Each repeated character adds minimal security. Ensure your password has genuine variety and randomness.
Short Passwords with Symbols
"P@ss1" might meet complexity requirements but is still very weak due to its short length. Don't sacrifice length for complexity. A 16-character lowercase password is stronger than an 8-character password with all character types.
Incremental Passwords
Changing "Password1" to "Password2" when forced to update is a common mistake. If one version is compromised, attackers will try incremental variations. Create completely new passwords for each update.
Trusting Password Requirements
Meeting minimum requirements (8 characters, 1 uppercase, 1 number) doesn't guarantee security. These are bare minimums. Aim higher - use 16+ characters with genuine randomness for important accounts.
Frequently Asked Questions
How does a password strength checker work?
Password strength checkers analyze multiple factors including length, character variety, entropy, patterns, and common password databases. They calculate how long it would take to crack the password using various attack methods and provide a strength score based on these factors.
Is it safe to check my password strength online?
Our password strength checker is completely safe because all analysis happens locally in your browser. Your password never leaves your device, is not sent to any server, and is not stored anywhere. We use client-side JavaScript for 100% privacy.
What makes a password strong?
A strong password has at least 12 characters, includes uppercase and lowercase letters, numbers, and symbols, avoids common words and patterns, has high entropy (randomness), and is not found in data breach databases. The best passwords are long, random, and unique.
What is password entropy?
Password entropy measures the randomness and unpredictability of a password in bits. Higher entropy means more possible combinations and greater security. A password with 60+ bits of entropy is considered strong, while 80+ bits is very strong.
How long should my password be?
Minimum 12 characters for good security, 16+ characters for strong security, and 20+ characters for maximum security. Length is one of the most important factors - a longer password with mixed characters is exponentially harder to crack than a short complex one.
What are common password patterns to avoid?
Avoid sequential characters (abc, 123), keyboard patterns (qwerty, asdf), repeated characters (aaa, 111), common substitutions (@ for a, 3 for e), dictionary words, personal information (names, dates), and passwords from data breaches.
Should I use a password manager?
Yes, password managers are highly recommended. They generate strong random passwords, store them securely, and auto-fill them when needed. This allows you to use unique, complex passwords for every account without memorizing them all.
How often should I change my passwords?
Change passwords immediately if you suspect a breach or if a service you use reports a security incident. Otherwise, strong unique passwords don't need regular changes. Forced frequent changes often lead to weaker passwords with predictable patterns.
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Conclusion
Password security is one of the most important aspects of online safety, yet many people still use weak, predictable passwords that can be cracked in seconds. Our password strength checker helps you understand what makes a password truly secure by providing detailed analysis of entropy, crack times, patterns, and vulnerabilities. By using this tool, you can make informed decisions about your password security and protect your accounts from unauthorized access.
Remember that password strength is just one part of account security. Always use unique passwords for each account, enable two-factor authentication when available, and consider using a password manager to generate and store complex passwords. Test your passwords regularly with our checker to ensure they meet modern security standards and stay protected against evolving threats.