Password Strength Checker
Test any password for entropy and crack difficulty. Nothing is uploaded.
This password strength checker analyzes any password you type and estimates its entropy in bits, based on the character pool size (lowercase, uppercase, digits, symbols) and length. A password under 40 bits is weak and can be cracked quickly by a modern GPU. Between 40 and 60 bits is fair. Between 60 and 80 bits is strong. Above 80 bits is excellent. Critically, this checker runs entirely in your browser — the password you type is never sent to any server, never logged, and never stored. You can verify this by opening your browser's DevTools Network tab after typing a password; you will see no requests. Use it to test new passwords before you use them, or to audit existing accounts.
Frequently Asked Questions
Is it safe to type my real password here?
Yes. The checker runs 100% locally in your browser. No password is uploaded, logged or stored. You can disconnect from the internet after the page loads and it still works.
How is strength calculated?
We estimate entropy = length × log2(pool size). Pool size is 26 for lowercase, +26 for uppercase, +10 for digits, +33 for symbols found in the password.
What makes a password strong?
Length matters most. A 12-character password with mixed character sets beats an 8-character complex password. Avoid dictionary words, common patterns and substitutions like "P@ssw0rd".