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Free Password Strength Checker

Test your password strength with detailed security analysis. Check entropy, crack time estimates, and get recommendations for improvement. All analysis happens locally in your browser.

Last Updated: 15 Jan 2026

Privacy Guarantee: Your password is processed locally in your browser and is never sent to our servers.

What is Password Strength?

Password strength is a measure of how resistant a password is to guessing and brute-force attacks. A strong password is essential for protecting your online accounts, personal data, and sensitive information from unauthorized access. Our password strength checker uses advanced algorithms to evaluate multiple factors that contribute to password security.

The strength of a password depends on several key factors: length, character diversity (uppercase, lowercase, numbers, symbols), randomness, and whether it appears in common password databases. Our tool analyzes all these aspects to give you a comprehensive security assessment, helping you understand how vulnerable your passwords are to various attack methods.

Why Use Our Free Password Strength Checker?

100% Secure & Private

All password analysis happens entirely in your browser. Your password never leaves your device, ensuring complete privacy and security. No server transmission, no storage.

Comprehensive Analysis

Get detailed metrics including entropy calculation, crack time estimates, character diversity analysis, and specific recommendations for improvement.

Instant Results

Analyze password strength instantly as you type. See real-time security metrics and get immediate feedback on how to improve your password security.

Common Use Cases for Password Strength Checker

Personal Security

Account Protection
Check passwords for email, banking, social media, and other critical accounts. Ensure your most important accounts have strong, secure passwords.
Password Creation
Test new passwords before using them to ensure they meet security requirements. Get instant feedback on password strength during creation.
Security Audits
Regularly audit your passwords to identify weak ones that need updating. Check existing passwords for security vulnerabilities.

Business & IT

Employee Password Policies
Verify employee passwords meet company security requirements. Ensure passwords comply with organizational password policies.
Security Training
Educate users about password security by demonstrating how different passwords score. Show the impact of length, complexity, and randomness.
Compliance Requirements
Ensure passwords meet regulatory requirements (GDPR, HIPAA, PCI-DSS). Verify passwords comply with industry security standards.

Key Password Strength Metrics

Entropy (Bits)

Measures the randomness and unpredictability of your password. Higher entropy (80+ bits) indicates a stronger password that's exponentially harder to crack.

Example: A 12-character random password with all character types has ~78 bits of entropy.

Crack Time Estimate

Estimates how long it would take to crack your password using modern brute-force methods. Strong passwords should take years or centuries to crack.

Example: A weak password might be cracked in seconds, while a strong one could take centuries.

Character Diversity

Evaluates the variety of character types used (uppercase, lowercase, numbers, symbols). Greater diversity significantly increases password strength.

Tip: Include all four character types for maximum security.

Length Analysis

Assesses password length, which is one of the most critical factors. Each additional character exponentially increases the number of possible combinations.

Rule: Longer passwords are exponentially stronger than shorter ones.

Common Password Weaknesses to Avoid

Dictionary Words

Passwords based on dictionary words, even with number substitutions (like "p@ssw0rd"), are vulnerable to dictionary attacks and can be cracked quickly. Attackers use wordlists containing millions of common passwords.

Personal Information

Avoid using birthdays, names, addresses, or other personal information that can be found on social media or public records. This information is easily discoverable and makes passwords predictable.

Sequential Patterns

Patterns like "123456", "qwerty", or "abcdef" are among the first combinations attackers try and offer virtually no security. These patterns are tested immediately in brute-force attacks.

Short Passwords

Passwords under 12 characters are significantly easier to crack. Always aim for 12-16+ characters for adequate security. Each additional character exponentially increases security.

Understanding Password Strength Levels

🔴 Weak Password

Entropy: Less than 40 bits | Crack Time: Seconds to minutes

Characteristics: Short length, dictionary words, predictable patterns, limited character types. These passwords can be cracked almost instantly.

🟠 Moderate Password

Entropy: 40-60 bits | Crack Time: Hours to days

Characteristics: Medium length, some character diversity, but still contains patterns or common words. Vulnerable to advanced attacks.

🟡 Good Password

Entropy: 60-80 bits | Crack Time: Weeks to years

Characteristics: Good length (12+ chars), multiple character types, some randomness. Suitable for most accounts but could be stronger.

🟢 Strong Password

Entropy: 80+ bits | Crack Time: Decades to centuries

Characteristics: Long length (16+ chars), all character types, high randomness, no patterns. Ideal for critical accounts and maximum security.

Frequently Asked Questions

Is it safe to check my password strength online?

Yes, our Password Strength Checker is completely safe because all analysis happens entirely in your browser using client-side JavaScript. Your password is never transmitted to our servers or stored anywhere. The analysis is performed locally on your device.

What is password entropy?

Password entropy measures the randomness and unpredictability of a password. It's calculated based on the character set size and password length. Higher entropy means a stronger password that takes longer to crack. Our tool calculates entropy in bits—the higher the number, the more secure your password.

How accurate are the crack time estimates?

Our crack time estimates are based on industry-standard calculations that assume modern brute-force attack speeds. However, actual crack times can vary based on the attacker's resources, attack method, and whether the password appears in common password lists or has been leaked in data breaches.

What makes a password strong according to this checker?

A strong password typically has high entropy (80+ bits), includes a mix of uppercase and lowercase letters, numbers, and special symbols, is at least 12-16 characters long, and doesn't contain dictionary words or predictable patterns. Our checker evaluates all these factors and provides a comprehensive strength score.