Password Entropy Calculator

Password Entropy Calculator

Entropy: 0 bits
Strength: Very Weak

Password Entropy Calculator

Use this free Password Entropy Calculator to check how strong your password is and learn how secure it would be against brute-force attacks. The entropy score tells you how unpredictable your password is based on character types and length.


🔹 What Is Password Entropy?

Password entropy is a measure of how difficult a password is to guess. It is calculated in bits, and the higher the entropy, the harder it is to crack your password using brute-force methods. This calculator uses character variety and length to compute the total entropy and estimate its strength level.


🔹 How to Use the Calculator

  1. Enter your password into the input box.
  2. See the calculated entropy in bits and its strength level.
  3. Try different combinations (symbols, numbers, mixed case) to increase security.
A strong password should have at least 60 bits of entropy.

🔹 Password Strength Levels

  • 0–27 bits: Very Weak
  • 28–35 bits: Weak
  • 36–59 bits: Reasonable
  • 60–127 bits: Strong
  • 128+ bits: Very Strong

🔹 Why Entropy Matters

Many websites only check for length or the presence of symbols, but true password strength comes from entropy. This tool gives a more technical and accurate evaluation, ideal for users serious about security, including:

  • Developers
  • IT administrators
  • Cybersecurity professionals
  • Regular users concerned about privacy

🔹 Frequently Asked Questions (FAQ)

Q: Is this calculator secure to use?

A: Yes. All calculations are done in your browser. No data is stored or sent anywhere.

Q: What is a good entropy score for a password?

A: Anything above 60 bits is considered strong. For high-security accounts, aim for 80+ bits.

Q: Can I use this to generate secure passwords?

A: While this tool is for checking entropy, you can use it to test passwords created with password generators.