Password Strength Checker
Test your password security instantly. Get real-time feedback on password strength, entropy, and estimated crack time. All checks happen in your browser—your password never leaves your device.
Interactive Password Strength Tester
Enter a password to see how strong it is. Try different combinations to see how they affect strength.
What Makes a Strong Password?
Length Matters Most
Aim for at least 12 characters. Each additional character exponentially increases crack time.
Use Character Variety
Mix uppercase, lowercase, numbers, and symbols. This increases the "character pool" and entropy.
Avoid Common Patterns
Don't use dictionary words, keyboard patterns (qwerty), or personal information (birthdays, names).
Password Security Tips
Never Reuse Passwords
Use a unique password for every account. If one site is breached, others remain safe.
Use a Password Manager
Let a password manager generate and store complex passwords for you. You only need to remember one master password.
Enable Two-Factor Authentication
Add an extra layer of security beyond your password. Even if your password is compromised, your account stays protected.
Understanding Password Entropy
Learn how password strength is calculated
What is Entropy?
Entropy measures the unpredictability of your password. It's calculated in bits, where each bit doubles the number of possible combinations. Higher entropy = harder to crack.
Entropy Scale
Very weak - cracked instantly
Weak - seconds to minutes
Moderate - hours to days
Strong - years to centuries
How It's Calculated
Entropy = log₂(character pool size ^ password length). For example, an 8-character password using only lowercase letters (26 characters) has 37.6 bits of entropy, while the same length with mixed case, numbers, and symbols (94 characters) has 52.4 bits.
Need a Strong Password?
Use our password generator to create secure passwords instantly