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Password Strength Checker

Check how strong your password is. We measure entropy, estimate how long it would take to crack, and give you specific recommendations to make it stronger. Nothing you type is sent to our servers.

Your password is never sent to our servers. All analysis runs locally in your browser.
Strength Score
0
out of 100
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Analysis
✗
At least 12 characters
✗
Uppercase letters (A-Z)
✗
Lowercase letters (a-z)
✗
Numbers (0-9)
✗
Special characters (!@#$%)
✗
Not a common password
Security Metrics
Entropy
0 bits
Crack Time (offline)
—
Character Pool
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What Makes a Strong Password?

Password strength is determined by two factors: length and character variety. A longer password with a mix of uppercase letters, lowercase letters, numbers and symbols has significantly more possible combinations, making it exponentially harder to crack by brute force.

A password like monkey123 can be cracked in under a second using a dictionary attack. A password like Tr7!kQpX#m2W would take millions of years to crack with current computing power. The difference is entropy — the amount of randomness in your password.

The most important rule is to never reuse passwords across sites. If one service is breached, all accounts using the same password become vulnerable. Use a password manager to generate and store unique strong passwords for every account.

How We Calculate Strength

Entropy (bits)
Calculated as: length × log2(character pool size). Higher entropy means more possible combinations and a stronger password. 60+ bits is good, 80+ bits is excellent.
Crack Time Estimate
Estimated time for an attacker using 10 billion guesses per second (offline hash cracking with a modern GPU cluster) to crack your password by brute force.
Common Password Check
We check against the most frequently used passwords and patterns. If your password appears on common lists, it can be cracked instantly regardless of apparent complexity.

Frequently Asked Questions

Is my password sent to your servers?
No. All password analysis runs entirely in your browser using JavaScript. Nothing you type is transmitted to our servers. You can disconnect from the internet and this tool will still work.
How long should my password be?
At minimum 12 characters for most accounts. For high-value accounts like email, banking or password managers, use 16 to 20 characters or more. Length is the single most effective way to increase password strength.
Are passphrases better than passwords?
Yes. A passphrase like correct-horse-battery-staple is longer, easier to remember, and has high entropy compared to a short complex password like P@ss1. Length matters more than complexity.
Should I use a password manager?
Yes. A password manager generates and stores unique strong passwords for every site so you only need to remember one master password. This eliminates the biggest password security risk: reuse across multiple sites.
What is a brute force attack?
A brute force attack tries every possible combination of characters until the correct password is found. Modern GPU clusters can test billions of combinations per second, which is why weak passwords are cracked almost instantly.
Does a strong password protect me from phishing?
No. Phishing attacks trick you into entering your password on a fake site, making strength irrelevant. Enable two-factor authentication on all important accounts and always verify URLs before entering credentials.