Tool · Password Strength Lab

How strong is that password, really?

Type anything below — nothing is sent anywhere or stored; it's all calculated right here in your browser. Try a real password, then try something obvious to see the difference.

Password Strength Lab

Live entropy calculator

Characters: 0
Pool size (depth): 0
Entropy: 0 bits

Online attack (1,000/sec): -
GPU cracking rig: -
Supercomputer: -

Why the "on a known list" check matters

A password can look complicated and still be worthless — if it's ever appeared in a real breach, it's likely sitting in a cracking dictionary already, and gets tried in seconds regardless of length. This is exactly the mechanism behind Case File #001: the RockYou breach.