Check how strong your password is with our free online password strength checker. Get instant analysis including entropy, crack time estimate, and improvement tips. 100% client-side.
This tool analyzes your password strength locally in your browser. We calculate entropy based on password length and character diversity, estimate crack time assuming a high-performance attacker, and check against common password lists. Your password never leaves your device.
Yes. This tool runs entirely in your browser — your password is never sent to any server. However, for maximum security, we recommend testing a password of similar complexity rather than your actual password.
Entropy measures the randomness of a password in bits. Higher entropy means the password is harder to guess through brute force. We calculate it as log2(charset_size ^ length).
Crack time is a rough estimate assuming an attacker can try 10 billion guesses per second using specialized hardware. In reality, online attacks are much slower, but offline attacks on leaked databases can be this fast.
A strong password is long (12+ characters), uses a mix of uppercase, lowercase, numbers, and symbols, avoids dictionary words and personal information, and is unique to each account.