Password Strength Checker

What is it and how does it work

How to check password strength

1. Type a password into the box — click "Show" if you want to see it as you type.
2. The strength meter, entropy estimate, and criteria checklist update instantly.
3. Use the checklist to see exactly what would make the password stronger.

Understanding the result

What makes a password strong

Password strength comes down to two things: length and unpredictability. A longer password with a mix of lowercase, uppercase, numbers and symbols has vastly more possible combinations than a short one, which is what entropy (measured in bits) is estimating — each additional bit doubles the number of guesses an attacker would need to try. As a rule of thumb, aim for at least 12 characters mixing multiple character types, and avoid dictionary words, names, or predictable patterns like "123" or "qwerty".

Everything you type here is analyzed locally in your browser and never transmitted anywhere — but as a general habit, it's still wise to avoid typing a real, currently-in-use password into any third-party website, including this one.

Most frequently asked questions

FAQ

Is this password strength checker really free, with no sign-up?+

Yes. The tool runs entirely with JavaScript in your browser — there's no account, no API key, and no limit on how often you can use it.

Is it safe to type my real password into this tool?+

The password is analyzed entirely in your browser using JavaScript and is never transmitted, stored, or logged anywhere. That said, as a general precaution it's still wise to avoid typing an active password into any third-party website.

How is the strength score calculated?+

The score considers total length and the variety of character types used (lowercase, uppercase, numbers, and symbols), and estimates entropy in bits based on the size of the character set and password length.

What is password entropy?+

Entropy measures how unpredictable a password is, expressed in bits. Higher entropy means more possible combinations an attacker would have to try, making the password harder to guess or brute-force.

What makes a strong password?+

A strong password is long (12+ characters), mixes uppercase, lowercase, numbers and symbols, and avoids common words, patterns, or personal information that could be guessed.

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Methodology

How This Checker Works

Your password is analyzed live with JavaScript, scoring length and character variety to estimate entropy — nothing you type is uploaded to a server, stored, or logged anywhere.

Last updated: August 28, 2026.