Password Strength Checker
Test how strong your password is. Get an entropy score, crack time estimate, and actionable improvement suggestions. Process data securely in your browser with no information transmitted to external servers..
What is Password Strength Checker | Rune
Password Strength Checker analyzes your password in real-time against multiple security criteria including length, character variety, common password databases, keyboard patterns, and sequential characters.
It calculates entropy (randomness in bits), estimates how long it would take to crack via brute-force at 10 billion guesses per second, and provides a detailed security checklist with improvement suggestions. Everything runs 100% in your browser, your password is never sent anywhere. Implements industry-standard cryptographic algorithms and security protocols for reliable results. All security operations run locally in your browser, ensuring sensitive data never leaves your device.
Key Features of Password Strength Checker
Everything you need for professional password strength checker
Comprehensive Scoring
Score from 0-100 based on length, character variety, patterns, and common password detection.
Crack Time Estimate
Estimates how long it would take to brute-force your password at 10 billion guesses per second.
Entropy Calculation
Calculates password entropy in bits, a mathematical measure of randomness and unpredictability.
Security Checklist
10 individual security checks with pass/fail indicators showing exactly what to improve.
Common Password Detection
Cross-references against a database of commonly used passwords that attackers try first.
100% Client-Side
Your password never leaves your browser. No network requests, no logging, complete privacy.
How to Use Password Strength Checker
Follow these simple steps to get started
Enter Password
Type or paste the password you want to check. Analysis starts immediately as you type.
Review Score
See your strength score, entropy, crack time estimate, and a visual progress bar.
Improve
Follow the security checklist and suggestions to strengthen your password.
Pro Tips
- Aim for at least 80/100 strength score. Passwords scoring below 40 can be cracked in minutes.
- Length matters more than complexity, a 20-character lowercase password is stronger than an 8-character mixed one.
- Avoid using personal information like birthdays, names, or pet names in passwords.
- Use a password manager to store unique, strong passwords for every account.
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Frequently Asked Questions
Everything you need to know about Password Strength Checker
Is my password safe when I type it here?
Yes. All analysis happens locally in your browser using JavaScript. Your password is never transmitted, logged, or stored anywhere. You can even disconnect from the internet and the tool will still work.
How is the crack time calculated?
We estimate crack time assuming an attacker making 10 billion guesses per second (modern GPU cluster). The time reflects brute-force search of the full character space for your password's length and complexity.
What is password entropy?
Entropy measures randomness in bits. Higher entropy means the password is harder to guess. It's calculated as: length × log₂(charset size). A 12-character password using all character types has about 79 bits of entropy.
Why does my password score low even though it looks complex?
Common passwords, keyboard patterns (qwerty, 1234), and repeated characters are heavily penalized. The tool checks for real-world attack patterns, not just character variety.
What score should I aim for?
Aim for 80+ (Strong or Very Strong). Scores below 40 are considered weak and vulnerable to brute-force attacks. Scores of 60-80 are fair but could be improved.
Does this tool check if my password has been leaked?
No. This tool analyzes password strength based on complexity and patterns. To check if your password appears in known data breaches, use a dedicated breach-checking service.
Is this tool free?
Yes, completely free with no limits. Check as many passwords as you want without signing up.
What makes a password 'Very Strong'?
A password scoring 80+ typically has 16+ characters, includes uppercase, lowercase, numbers, and symbols, avoids common words and patterns, and has high entropy.
Still need help?
Can't find what you're looking for? Our support team is here to assist you.
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