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Password Entropy Calculator

Bits of entropy from length and charset size (with presets).

Free to use — no sign-up or login.

Entropy (bits)

This free Password Entropy Calculator covers Bits of entropy from length and charset size (with presets).

Entropy ≈ length × log2(charset size). Related other tools sit beside How it works, with no account required.

Using the Password Entropy Calculator

Bits of entropy from length and charset size (with presets). Typical inputs are Length, Charset and Custom charset size. How it works beside the form states the identity the Password Entropy Calculator applies.

FAQ

How do I use the Password Entropy Calculator?

Open the Password Entropy Calculator, fill Length, Charset and Custom charset size, and read the result. Choose a charset preset or enter a custom size, then multiply by length.

What formula does the Password Entropy Calculator use?

The Password Entropy Calculator uses the identity in How it works. In words: Choose a charset preset or enter a custom size, then multiply by length.