Password Strength Checker
Type or paste a password to instantly see its strength, entropy, estimated crack time, and specific tips to improve it. Nothing leaves your browser.
| Attack scenario | Speed | Time to crack |
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What is Password Strength?
Password strength measures how resistant a password is to guessing attacks. Strength is determined by length, character variety, and unpredictability. Longer, more complex passwords with a mix of uppercase, lowercase, numbers, and symbols are dramatically stronger than short or dictionary-based passwords.
This tool analyses a password and shows its entropy in bits, crack time estimates at different attack speeds, and specific improvement tips.
How to check password strength online
- Type your password into the input field.
- The tool shows the entropy score, strength rating, and crack time estimate.
- Read the tips to understand how to make the password stronger.
Frequently Asked Questions
What is entropy in password analysis?
Entropy measures unpredictability in bits. A password with 40 bits of entropy has 2 to the power of 40 (about 1 trillion) possible values. Each additional bit doubles the number of guesses required. A minimum of 60-80 bits is recommended for high-security passwords.
What makes a password weak?
Common weaknesses: short length (under 10 characters), dictionary words, predictable substitutions (pa$$word), keyboard patterns (qwerty, 123456), and reuse across multiple accounts.
How long does it take to crack an 8-character password?
A modern GPU can try over 10 billion password hashes per second. An 8-character password using only lowercase letters could be cracked in under a minute. Adding uppercase, numbers, and symbols to the same length increases the time — but 12 or more characters is far safer.
What is the difference between password strength and password security?
Strength measures resistance to guessing. Security also depends on how the password is stored (bcrypt vs MD5), whether you reuse it across sites, and whether you have two-factor authentication enabled.