Password Strength Checker
Estimate strength locally in your browser (no uploads, no logging)
—
Entropy
—
Online
—
Offline
—
Notes
—
Checks
Start typing…
Runs entirely in your browser. Nothing is sent or stored.
What this checks
This tool estimates strength based on length, character variety, and common weak patterns (like repeats and sequences). It gives a practical score and suggestions — all locally.
How to use the estimate
“Online” assumes rate limits (e.g., login throttling). “Offline” assumes a stolen hash and fast guessing. Real-world outcomes depend on hashing (bcrypt/argon2), rate limits, and MFA.
Better than “complexity rules”
A longer password or passphrase is usually stronger than a short “complex” one. Aim for 16+ characters or use a 6–8 word Diceware passphrase.