Password Strength Meter

Evaluate password security with entropy analysis and crack time estimation

Password Strength Meter

Evaluate password security with entropy analysis and crack time estimation

Enter Password

What is a Password Strength Meter?

A password strength meter is a security tool that evaluates the robustness of passwords based on multiple factors including length, character diversity, and entropy. Our tool provides real-time analysis with crack time estimation, helping you create stronger, more secure passwords for your accounts.

How Password Strength is Calculated

1. Character Pool Size

The tool first determines which character types are used in your password:

Lowercase letters (a-z): 26 characters
Uppercase letters (A-Z): 26 characters
Numbers (0-9): 10 characters
Symbols (!@#$%...): 32 characters

2. Entropy Calculation

Entropy measures password randomness using the formula:

Entropy = log₂(pool_size^length)

Higher entropy means more possible combinations, making the password harder to crack.

3. Crack Time Estimation

We estimate how long it would take to crack your password using a modern GPU capable of 10 billion guesses per second. This gives you a realistic understanding of password security.

4. Strength Score

Based on entropy and length, passwords are scored from 0-4:

Very Weak (0): <28 bits entropy or <6 characters
Weak (1): 28-35 bits entropy or 6-7 characters
Medium (2): 36-59 bits entropy or 8-9 characters
Strong (3): 60-79 bits entropy or 10-11 characters
Very Strong (4): 80+ bits entropy or 12+ characters

Key Features

⚡ Real-Time Analysis

Instant feedback as you type with zero lag.

📊 Entropy Calculation

Precise entropy measurement in bits.

⏱️ Crack Time Estimation

Realistic time-to-crack estimates.

💡 Smart Suggestions

Actionable tips to improve password strength.

🔄 Password Comparison

Compare up to 5 passwords side-by-side.

💾 History & Export

Save analyses and export as TXT or JSON.

How to Use

Single Password Analysis

Type or paste your password in the input field
View real-time strength analysis with color-coded bar
Check entropy score and estimated crack time
Review character type usage (uppercase, lowercase, numbers, symbols)
Read suggestions for improving password strength
Save analysis to history or export results

Password Comparison

Switch to "Compare Passwords" mode
Enter multiple passwords (up to 5)
Label each password for easy identification
View side-by-side strength comparison
Check comparison summary table
Export comparison results as TXT or JSON

Password Strength Guidelines

✅ Do This

Use at least 12 characters (16+ recommended)
Mix uppercase, lowercase, numbers, and symbols
Use unique passwords for each account
Consider using passphrases (e.g., "Coffee-Mountain-Purple-42!")
Use a password manager to store complex passwords
Enable two-factor authentication (2FA) when available

❌ Avoid This

Don't use common words or phrases (password, admin, welcome)
Avoid personal information (birthdays, names, addresses)
Don't use keyboard patterns (qwerty, asdfgh, 123456)
Avoid repeated characters (aaa, 111, !!!)
Don't use sequential patterns (abc, 123, xyz)
Never reuse passwords across multiple accounts

Understanding Entropy

Entropy is a measure of password randomness and unpredictability. Higher entropy means more possible combinations, making brute-force attacks exponentially harder.

Entropy (bits)	Strength	Example	Crack Time
< 28 bits	Very Weak	pass123	Instant
28-35 bits	Weak	Password1	Minutes
36-59 bits	Medium	Pass@word123	Days to months
60-79 bits	Strong	MyP@ssw0rd!2024	Years to centuries
80+ bits	Very Strong	Tr0pic@l-M0unt@in-42!	Millennia+

Common Use Cases

🔐 Account Security Audit

Test your existing passwords to identify weak ones that need updating.

🆕 New Password Creation

Evaluate new passwords before using them to ensure they meet security standards.

👥 Team Password Policy

Establish minimum password requirements for your organization based on entropy scores.

📚 Security Education

Teach users about password security by showing real-time strength analysis.

🔄 Password Comparison

Compare multiple password options to choose the strongest one for critical accounts.

Frequently Asked Questions

Is it safe to enter my password here?

Yes! All analysis happens locally in your browser. No passwords are sent to any server or stored anywhere except your device's localStorage (if you choose to save history).

What makes a password strong?

A strong password has high entropy (80+ bits), uses all character types (uppercase, lowercase, numbers, symbols), is at least 12 characters long, and avoids common patterns or words.

How accurate is the crack time estimation?

Our estimates assume a modern GPU capable of 10 billion guesses per second in an offline attack. Real-world crack times vary based on attack method, hardware, and security measures like rate limiting.

Should I use a password manager?

Absolutely! Password managers generate and store complex, unique passwords for each account, making them much more secure than reusing simple passwords.

What's the difference between entropy and strength?

Entropy is a mathematical measure of randomness (in bits), while strength is a user-friendly rating (Very Weak to Very Strong) based on entropy, length, and character diversity.

Can I export my password analysis?

Yes! You can export individual analyses or comparison results as TXT or JSON files for documentation or security audits.

Password Security Best Practices

Length matters most: A 16-character password with mixed case is stronger than an 8-character password with all character types.

Use passphrases: Combine random words with numbers and symbols (e.g., "Coffee-Mountain-Purple-42!").

Unique passwords: Never reuse passwords across different accounts or services.

Enable 2FA: Two-factor authentication adds an extra security layer beyond passwords.

Regular updates: Change passwords periodically, especially for critical accounts.

Password manager: Use a reputable password manager to generate and store complex passwords.

This password strength meter is a free, privacy-focused tool designed to help you create stronger passwords. All analysis is performed locally in your browser with no server communication.

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