🔐 Password Strength Checker

This tool analyzes your password's entropy (in bits) and estimated crack time based on its character makeup and length. All calculations happen entirely in your browser, so your password is never sent or stored anywhere.

How to use

1. Type the password you want to check and its strength is calculated in real time.
2. Click 'Show' to reveal what you typed, or hide it again.
3. Review the strength bar, entropy, estimated offline and online crack times, and the requirements checklist.
4. Fix any items marked with ✗ on the checklist (length, upper/lowercase, numbers, special characters, etc.) to raise the strength.

FAQ

How is the estimated crack time calculated?

We compute the number of possible combinations as the character set size raised to the length power, assume that on average half of them must be tried, then divide by the speeds of offline high-speed cracking (10 billion guesses per second) and online guessing attacks (1,000 per second) to estimate the time.

Could my password be leaked?

No, it's safe. Your input is processed only in browser memory and is never sent over the network or saved locally. Even so, it's best not to enter a password you actually use on a shared PC.

Can I fully trust the crack time shown?

This is a theoretical upper-bound estimate that only considers character combinations, so it can differ from reality and is for reference only. Dictionary attacks, guesses based on personal information, and repeated patterns greatly lower real security, so use a long, hard-to-predict, unique password together with two-factor authentication.