Free Password Strength Checker: Entropy & Crack Time Online
Check how secure your password is: entropy, crack time and tips to improve it.
Type a password and instantly see its security level, how many bits of entropy it has and how long brute force would take to crack it.
By VOV · Last updated: October 21, 2026
How it works
How it works: the character set used (lowercase, uppercase, digits, symbols) and length are analyzed to compute entropy in bits. Crack time assumes 10 billion guesses per second, the rate of a modern GPU attack. Everything is computed in your browser; your password is never sent to any server.
Use cases
- Check whether your current password would survive a brute-force attack before you decide to change it
- Verify the strength of your WiFi key so the neighbors can't secretly connect without permission
- Evaluate whether your online banking password is really strong enough to keep the hackers out
Frequently asked questions
Is my password sent to any server?
No. The analysis is a local mathematical computation in your browser. Your password never leaves your device.
What is entropy?
It measures unpredictability in bits: each bit doubles the possible combinations. 80+ bits is considered safe against current brute force.
Is the crack time exact?
It is an estimate with modern hardware (10 billion guesses/second). An attacker with more resources would take less; with unique passwords and a password manager you are fine.
How do I create a very strong password?
Use our password generator: 16+ random characters with all four symbol types. Store it in a manager, not in your memory.