Advanced Password Strength Checker
Enter a password to see its strength
Detailed Analysis & Recommendations
Detailed analysis will appear here.
Entropy
N/A
Est. Crack Time
N/A
Length
0
Character Types
None
Common Password?
N/A
Tips for Creating Strong Passwords
- Length is key: Aim for at least 16 characters.
- Mix it up: Use uppercase, lowercase, numbers, and symbols.
- Avoid the obvious: Don't use personal info or dictionary words.
- Be unique: Use different passwords for different accounts.
- Use a password manager: To generate and store complex passwords.
- Enable Two-Factor Authentication (2FA): For an extra layer of security.
Your Privacy is Protected
This tool analyzes passwords entirely within your browser. No data is sent to our servers. You can use this tool offline for maximum privacy.
Understanding Password Strength
Password strength isn't just about length; it's about complexity and unpredictability. A strong password should be difficult for both humans and computers to guess.
Key Factors in Password Strength:
- Entropy: A measure of a password's randomness. Higher entropy means a stronger password.
- Character Set Size: The number of possible characters used (e.g., 26 for lowercase, 94 for all types).
- Length: Each additional character exponentially increases the number of possible combinations.
- Unpredictability: Avoidance of common words, phrases, or patterns.
Our tool uses these factors, including checks against common password lists (simulated for this client-side demo), to provide a comprehensive strength score.
About Password Strength Checker
What does this tool do?
Our Advanced Password Strength Checker analyzes password security using entropy calculations, character complexity analysis, common password detection, and advanced pattern recognition. It provides real-time feedback with detailed recommendations to improve password strength and resistance against various attack methods.
Why is this useful?
Password strength analysis helps identify vulnerabilities before they become security risks. Our tool evaluates passwords against modern attack techniques including brute force, dictionary attacks, and pattern recognition to ensure your credentials provide adequate protection.
Who uses this tool?
- Individual users - Evaluate personal password security before account creation
- Security professionals - Assess password policies and user compliance
- IT administrators - Test password requirements and validation rules
- Developers - Integrate password strength validation into applications
- Cybersecurity educators - Demonstrate password security concepts and best practices
How to check password strength
- Enter your password in the secure input field (data stays in your browser)
- Review the overall strength meter and classification (Weak/Moderate/Strong)
- Examine detailed metrics: entropy, estimated crack time, character types
- Read the specific feedback and recommendations for improvement
- Check if the password appears in common password databases
- Apply suggestions to create a stronger, more secure password
Example
Testing "password123" reveals: low entropy (42 bits), vulnerable to dictionary attacks, appears in common password lists, and can be cracked in hours. Upgrading to "K#7mP2$vN9@xL4wQ" shows high entropy (106 bits) with centuries of crack time.
Understanding password analysis results
- Entropy Score
- Measures password randomness in bits. Higher entropy indicates greater unpredictability and security against brute force attacks.
- Estimated Crack Time
- Theoretical time required to crack the password using modern computing power and sophisticated attack methods.
- Character Types Analysis
- Evaluates use of uppercase, lowercase, numbers, and symbols. More character types exponentially increase password strength.
- Common Password Detection
- Checks against databases of frequently used passwords that are easily compromised in attacks.
- Pattern Recognition
- Identifies predictable sequences, repetitions, and substitutions that reduce password security.
Strong password indicators
- High entropy (70+ bits): Indicates excellent randomness and unpredictability
- Long crack time (years+): Resistant to current and near-future attack methods
- Mixed character types: Uses all four character classes effectively
- No common patterns: Free from dictionary words, sequences, and repetitions
Weak password indicators
- Low entropy (under 40 bits): Vulnerable to brute force attacks
- Short crack time (days or less): Can be compromised quickly
- Limited character types: Reduces possible combinations significantly
- Common password match: Appears in breach databases and attack lists
Important security considerations
- Even strong passwords can be compromised through phishing or malware
- Password reuse across accounts multiplies security risks exponentially
- Social engineering attacks can bypass technical password strength
- Two-factor authentication provides crucial additional security layers
- Regular password updates help mitigate unknown breaches
Common use cases
Personal Security Audit
Evaluate existing passwords for email, banking, and social media accounts to identify weak credentials that need upgrading.
Password Policy Development
Test organizational password requirements and validate that policies actually produce strong, secure passwords for employees.
Security Training
Demonstrate password security concepts, showing how small changes dramatically impact strength and resistance to attacks.
Application Development
Test password validation algorithms and user interfaces to ensure effective security guidance during account creation.
Privacy and security
All password analysis occurs entirely in your browser using client-side JavaScript. No passwords are transmitted to our servers, ensuring complete privacy and security during analysis.
Technical analysis methods
Our tool combines entropy calculation, character set analysis, pattern detection, and common password checking to provide comprehensive security assessment using industry-standard methodologies.
Detailed analysis will appear here.
';
entropyValueEl.textContent = 'N/A';
crackTimeValueEl.textContent = 'N/A';
lengthValueEl.textContent = '0';
charTypesValueEl.textContent = 'None';
commonPasswordValueEl.textContent = 'N/A';
commonPasswordValueEl.className = 'metric-value';
commonPasswordDetailsEl.textContent = '';
}
function analyzePassword(password) {
if (password.length === 0) {
resetAnalysisUI();
return;
}
// Basic character type checks
const length = password.length;
const hasUpper = /[A-Z]/.test(password);
const hasLower = /[a-z]/.test(password);
const hasNumbers = /[0-9]/.test(password);
const hasSymbols = /[^A-Za-z0-9]/.test(password);
let score = 0;
let charPoolSize = 0;
const feedback = [];
// Length
lengthValueEl.textContent = length;
if (length < 8) {
score -= 30;
feedback.push({ text: 'Too short. Aim for at least 8 characters (16+ recommended)._icon fa fa-times-circle bad' });
} else if (length < 12) {
score += 10;
feedback.push({ text: 'Good length, but longer is better._icon fa fa-check-circle warning' });
} else {
score += 25;
feedback.push({ text: 'Excellent length!_icon fa fa-check-circle good' });
}
// Character types
let typesCount = 0;
let charTypesUsed = [];
if (hasUpper) { typesCount++; score += 10; charPoolSize += 26; charTypesUsed.push('AZ'); }
if (hasLower) { typesCount++; score += 10; charPoolSize += 26; charTypesUsed.push('az'); }
if (hasNumbers) { typesCount++; score += 10; charPoolSize += 10; charTypesUsed.push('09'); }
if (hasSymbols) { typesCount++; score += 20; charPoolSize += 32; charTypesUsed.push('#!'); } // Assume ~32 common symbols
charTypesValueEl.textContent = charTypesUsed.join(', ') || 'None';
if (typesCount < 2 && length > 0) {
feedback.push({ text: 'Include more character types (e.g., uppercase, numbers, symbols)._icon fa fa-exclamation-triangle warning' });
} else if (typesCount < 4 && length > 0) {
feedback.push({ text: `Using ${typesCount} character types. Consider adding all four for maximum strength._icon fa fa-info-circle warning` });
} else if (typesCount === 4) {
feedback.push({ text: `Great! Using all four character types._icon fa fa-check-circle good` });
}
// Entropy
const entropy = length * (Math.log2(charPoolSize > 0 ? charPoolSize : 1));
entropyValueEl.textContent = `${entropy.toFixed(2)} bits`;
score += Math.min(30, Math.floor(entropy / 2)); // Add entropy to score, capped
// Estimated crack time (simplified)
const guessesPerSecond = 1e9; // 1 billion guesses/sec
const combinations = Math.pow(charPoolSize > 0 ? charPoolSize : 1, length);
const secondsToCrack = combinations / guessesPerSecond;
let crackTimeText = 'Astronomical';
if (secondsToCrack < 1) crackTimeText = 'Instantly';
else if (secondsToCrack < 60) crackTimeText = `< 1 minute`;
else if (secondsToCrack < 3600) crackTimeText = `${Math.round(secondsToCrack / 60)} minutes`;
else if (secondsToCrack < 86400) crackTimeText = `${Math.round(secondsToCrack / 3600)} hours`;
else if (secondsToCrack < 2592000) crackTimeText = `${Math.round(secondsToCrack / 86400)} days`;
else if (secondsToCrack < 31536000) crackTimeText = `${Math.round(secondsToCrack / 2592000)} months`;
else if (secondsToCrack < 31536000 * 100) crackTimeText = `${Math.round(secondsToCrack / 31536000)} years`;
crackTimeValueEl.textContent = crackTimeText;
if (secondsToCrack < 86400 * 30) { // Less than a month
score -=15;
feedback.push({text: 'Estimated crack time is relatively short. Increase length or complexity._icon fa fa-exclamation-triangle warning'});
}
// Common password check
const lowerPassword = password.toLowerCase();
if (commonPasswords.has(lowerPassword)) {
score -= 50;
feedback.push({ text: 'This is a very common password and easily guessed!_icon fa fa-ban bad' });
commonPasswordValueEl.textContent = 'Found!';
commonPasswordValueEl.className = 'metric-value found';
commonPasswordDetailsEl.textContent = 'Appears in common password lists.';
} else {
commonPasswordValueEl.textContent = 'Not Found';
commonPasswordValueEl.className = 'metric-value not-found';
commonPasswordDetailsEl.textContent = 'Does not appear in our sample common password list.';
score +=5; // Small bonus for not being common
}
// Sequential characters check (e.g., 'abc', '123')
if (/(abc|bcd|cde|def|efg|fgh|ghi|hij|ijk|jkl|klm|lmn|mno|nop|opq|pqr|qrs|rst|stu|tuv|uvw|vwx|wxy|xyz)/.test(lowerPassword) ||
/(012|123|234|345|456|567|678|789)/.test(password)) {
score -= 10;
feedback.push({ text: 'Avoid sequential characters (e.g., 'abc', '123')._icon fa fa-minus-circle warning' });
}
// Repeated characters check (e.g., 'aaa', '111')
if (/(.)\1\1/.test(password)) {
score -= 10;
feedback.push({ text: 'Avoid repeating characters (e.g., 'aaa', '111')._icon fa fa-minus-circle warning' });
}
// Normalize score (0-100)
score = Math.max(0, Math.min(100, score));
// Update overall strength bar and text
overallStrengthBar.style.width = `${score}%`;
if (score < 33) {
overallStrengthBar.style.backgroundColor = '#dc3545'; // Red
overallStrengthText.textContent = 'Weak';
} else if (score < 66) {
overallStrengthBar.style.backgroundColor = '#ffc107'; // Yellow
overallStrengthText.textContent = 'Moderate';
} else {
overallStrengthBar.style.backgroundColor = '#28a745'; // Green
overallStrengthText.textContent = 'Strong';
}
if (length === 0) overallStrengthText.textContent = 'Enter a password to see its strength';
// Display detailed feedback
feedbackContent.innerHTML = '';
if (feedback.length > 0) {
const ul = document.createElement('ul');
ul.classList.add('feedback-list');
feedback.forEach(item => {
const [text, iconClass] = item.text.split('_icon ');
const li = document.createElement('li');
li.classList.add('feedback-item');
li.innerHTML = ` ${text}`;
ul.appendChild(li);
});
feedbackContent.appendChild(ul);
} else if (password.length > 0) {
feedbackContent.innerHTML = 'Looks good! Review metrics below.
';
}
}
// Initial state
resetAnalysisUI();
});