Password Strength Checker
See how strong your password really is — with estimated crack time and a criteria checklist.
🔒 Your password never leaves your browser.
How the Password Strength Checker Works
Type a password to get an instant strength score from 0 (Very Weak) to 4 (Very Strong). The score is based on length, character diversity (uppercase, lowercase, digits, symbols), and detection of common patterns or sequential characters.
The estimated crack time is calculated from the password's entropy (information content) assuming an attacker using a modern GPU at 10 billion guesses per second. All analysis happens locally in your browser — your password is never transmitted.
Frequently Asked Questions
What makes a password strong?
A strong password combines length (16+ characters), variety (uppercase, lowercase, digits, and symbols), and unpredictability (no dictionary words, sequential patterns, or common substitutions like 3 for e).
What is entropy?
Entropy measures the unpredictability of a password in bits. A higher entropy means more possible combinations an attacker must try. Each additional character roughly multiplies the number of possibilities by the charset size.
Is my password safe to enter here?
Yes. This tool runs entirely in your browser — no network requests are made and your password is never sent anywhere. You can verify this by disconnecting from the internet and testing.
What score should I aim for?
Aim for a score of 3 (Strong) or 4 (Very Strong) for accounts that matter. For critical accounts (email, banking, work), also consider using a password manager to generate and store truly random passwords.
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