Password Strength Checker
Test your password strength with entropy analysis and a checklist.
🔒 Tested locally in your browser. Your password is never sent anywhere.
What Is This Tool?
This tool analyzes your password's strength in real time and shows the estimated entropy, a strength rating, and a checklist of what would make it stronger. Everything runs in your browser — your password is never transmitted or stored.
How Strength Is Measured
Strength is based on entropy — the number of possible combinations an attacker would need to try. Longer passwords with more character types have higher entropy. A 12-character password using all four types (upper, lower, numbers, symbols) has about 78 bits of entropy, which is effectively uncrackable.
Strength Levels
- Very Weak (<40 bits): Crackable in seconds. Never use.
- Weak (40-60 bits): Hours to days to crack.
- Strong (60-80 bits): Years to crack. Good for most accounts.
- Very Strong (>80 bits): Uncrackable. Use for email, banking, password managers.
Why Length Matters Most
Adding length increases entropy exponentially, while adding character types increases it linearly. A 16-character lowercase password (75 bits) is stronger than an 8-character password using all four types (52 bits). When in doubt, go longer.
Frequently Asked Questions
Is it safe to type my real password here?
Yes. This tool processes everything locally in your browser. There is no network request — your password never leaves your device. You can also test variations.
What if my password is in a data breach?
Strength only measures guessability, not whether it has been leaked. Check Have I Been Pwned to see if your password has appeared in known breaches.
About the Password Strength Checker
The Password Strength Checker handles password strength checkerdirectly in your browser. Paste or type your input, and the tool processes it instantly — no upload, no signup, no waiting. It's built for the moments when you need a quick transformation and don't want to leave your workflow.
Because the tool runs client-side, it's fast and private. Your text never touches a server, which makes it safe for sensitive content. The interface is keyboard-friendly and works on any device with a modern browser.
How to Use This Tool
- Paste or type your input into the text area.
- Adjust any options the tool offers.
- The output updates automatically as you type or change options.
- Copy the result using the copy button.
Why Use an Online Tool?
Browser-based tools like this one have a few real advantages over installed software or manual methods:
- No installation. It opens instantly in any browser, on any operating system.
- Private by default. Everything runs locally, so your data stays on your device.
- Always up to date.There's nothing to update — you always get the latest version when you load the page.
- Free and unlimited. Use it as often as you like, with no account and no caps.
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