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Utility Calculators

Password Entropy Calculator

Verified formula Updated Jun 2026 Private — runs on your device

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Verified formula Private

Entropy

78.7

Possible combinations (log10)
23.7

For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.

How to use the Password Entropy Calculator

The Password Entropy Calculator works out your entropy, along with 1 related figure in an instant. Enter password length and character set size and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.

  1. Enter the password length.
  2. Enter the character set size.
  3. Read off your entropy, together with possible combinations (log10) — the calculator updates automatically, with no button to press.

Worked example

For example, with password length of 12 and character set size of 94, the entropy is 78.7.

Inputs used
Password length 12
Character set size 94
Results
Entropy 78.7
Possible combinations (log10) 23.7

Results are estimates for educational use, not professional advice.

Frequently asked questions

Entropy in bits = length × log₂(character set size). A 12-character password from a 94-character set has about 79 bits.

Lowercase only is 26, adding uppercase 52, adding digits 62, and adding common symbols about 94.

Around 60 bits resists casual attacks, and 80 bits or more is strong against serious brute forcing. Longer is better.

No. Reused or guessable passwords are weak regardless of entropy. Use unique, random passwords and a password manager.

Enter the password length. Enter the character set size. Read off your entropy, together with possible combinations (log10) — the calculator updates automatically, with no button to press.

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