About the Password Strength & Entropy Calculator
How strong is a password really? This calculator estimates entropy from length and the character sets used, penalizes common sequences, repeated characters and well-known passwords, and estimates how long an offline attack at 10 billion guesses per second would take on average.
The password is analysed in your browser only — it is never transmitted.
How to use it
- Type or paste a password.
- Read the entropy, strength rating and estimated crack time.
- Follow any warnings to improve it.
Good to know
- Entropy estimates assume random characters. Human-chosen passwords are usually much weaker than the math suggests.
- Avoid typing passwords you actually use into any website; test similar examples instead.