Password Strength Checker
Type a password to see its estimated crack time and how to strengthen it. Everything is computed on your device — nothing is sent or stored.
*Assuming an offline attack at 10 billion guesses per second.
What makes a password strong?
Strength comes from length and unpredictability. Each extra character multiplies the search space; a password found in a breach dictionary is weak no matter how complex it looks. Best practice: 16+ random characters from a password manager, or a passphrase of 4–5 unrelated words. Never reuse passwords across sites.
Frequently asked questions
Can this tool steal my password?
No. The analysis runs in a few lines of JavaScript on your own device. There is no upload, no analytics on the field, and no storage — reload the page and it is gone.
Why does “P@ssw0rd” score badly despite symbols?
Because attackers know these substitutions. This checker includes a dictionary of the most-breached passwords and their common variants, which override raw math — a pattern attackers try first is effectively a 1-guess password.