Password Strength Checker
See how strong your password is, based on length, character variety, and common weak patterns — analyzed entirely in your browser.
🔒 Processed locally in your browser
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How to use
- Type or paste a password into the field above — it's analyzed locally as you type, nothing is sent anywhere.
- Click "Show" if you want to see the characters instead of the masked dots.
- Watch the strength meter, label, and estimated entropy update live below the field.
- Check the character variety checklist and any warnings to see exactly what to improve.
Features
- Live analysis as you type — no button to press
- Checks length, character variety, and estimated entropy
- Flags common weak passwords, sequential patterns, and repeated characters
- Show/hide toggle so you can verify what you typed
- 100% client-side — your password is never sent, stored, or logged
Frequently asked questions
Is my password sent to a server or stored anywhere?
No. Every check runs entirely in your browser using local JavaScript. Your password is never sent over the network, never stored, and never logged — not even temporarily.
Does this check my password against a breach database like Have I Been Pwned?
No. This tool only uses local heuristics — length, character variety, an entropy estimate, and a small built-in list of common weak passwords — and never queries any external API or breach database.
How is the strength score calculated?
It combines password length, character variety (lowercase, uppercase, numbers, symbols), an estimated entropy in bits, and penalties for common passwords, sequential patterns (like "abcd"), and repeated characters (like "aaaa").
What does "entropy" mean here?
Entropy is a rough estimate of how unpredictable a password is, measured in bits, based on its length and the range of characters it uses. Higher entropy generally means more possible combinations to guess.
Should I reuse a password that scores "Very Strong" here?
No — always use a unique password for every account, ideally generated and stored with a password manager. A high score here just means the password itself is hard to guess, not that reusing it is safe.