HomeCybersecurityPassword Strength & Entropy Checker

🔑 Password strength & entropy checker

Measure how strong a password really is — entropy in bits, estimated offline crack time and a plain-language weakness check — then generate a cryptographically secure password or passphrase. Everything runs in your browser; the password is never sent anywhere. Aligned to NIST SP 800-63B.

🔒 Privacy: This tool is 100% client-side. Anything you type stays in your browser — it is never sent to a server, never logged and never saved. There are no network requests with your password and nothing is stored. Close the tab and it is gone.
1 — Check a password
Findings
2 — Generate a strong secret
20

⚠️ Entropy and crack-time figures assume an offline attacker who has the password hash and tries it against a fast hash; they are order-of-magnitude estimates, not guarantees, and assume a password chosen at random. Real attackers use breached-password and dictionary lists, so a "high-entropy-looking" but common or predictable password can fall instantly. Use a password manager, enable multi-factor authentication, and never reuse passwords. This tool gives general guidance, not a security audit, and stores nothing.