Password Entropy Calculator

Use a uniform independent-draw model for random passwords; do not interpret the result as measured entropy or crack time for human-chosen passwords.

Password length

Alphabet size

Target bits

—Theoretical bits

—Length for target

—Combinations

—Alphabet

Formula: length × log₂(alphabet size). This is exact for independent uniform random draws from the stated alphabet, not for human-selected passwords.

Sensitive values stay in this browser page. Theoretical entropy/search-space math assumes uniform random generation and is not a crack-time promise for human-chosen passwords. Use a reputable password manager for real account storage.

How to use this Password Entropy Calculator

Calculate theoretical password entropy, minimum length for a target bit level, and exact search-space combinations. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.