Password Strength Checker — Free Online Tool
Test how strong a password is — entirely in your browser, never uploaded.
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0Length
0Entropy (bits)
—Est. crack time
About Password Strength Checker
The Password Strength Checker rates how strong a password is based on its length and character variety, estimates its entropy in bits, and shows a rough offline crack-time. It also gives practical tips to make weak passwords stronger.
Crucially, your password never leaves your browser — there are no uploads and nothing is stored. Use it to sanity-check a password before you commit to it.
How to Use Password Strength Checker
- Type or paste a password into the box.
- Watch the strength meter, entropy, and crack-time update live.
- Follow the suggestions to strengthen weak passwords.
- Toggle visibility to check what you typed.
Key Features
Live strength meter and rating
Entropy (bits) and estimated crack time
Actionable improvement tips
Nothing is uploaded or stored
100% client-side and private
Frequently Asked Questions
How is password strength measured?
The checker estimates entropy from the length and the mix of character types (lowercase, uppercase, digits, symbols), then maps it to a strength rating and a rough offline crack-time estimate.
Is my password sent anywhere?
No. The check runs entirely in your browser — your password is never transmitted, logged, or stored.
What makes a strong password?
Length is the biggest factor. A long passphrase with a mix of character types and no common words or patterns is far stronger than a short complex one.
Should I reuse passwords?
No. Use a unique password for each account and a password manager to store them. This tool helps you judge strength before you save one.