Entropy Calculator

Estimate the entropy and brute-force time of a secret.

Password, key, or token

What Is a Entropy Calculator?

The Entropy Calculator estimates the entropy of a password, key, or token in bits based on its length and the variety of characters used. It also estimates how long it would take to crack the secret by brute force at 10 billion guesses per second, giving a practical sense of its strength.

How to Use This Entropy Calculator

1
Type a secretEnter a password, key, or token.
2
Read the estimateSee the entropy in bits and the estimated strength.
3
Review the crack timeUnderstand how long a brute-force attack would take.

Frequently Asked Questions

For important secrets, aim for 80 bits or more. Values below about 60 bits become increasingly vulnerable to distributed brute-force attacks.

Each additional character multiplies the number of possible combinations exponentially, so length contributes more to entropy than any single character type.

It is an approximation. Actual cracking time depends on the attacker's hardware, but the estimate gives a useful scale of the secret's strength.

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