Password Strength Checker

Test password strength, estimate entropy bits, and identify vulnerabilities such as dictionary words, repeated patterns, and short lengths.

Summary:A password strength checker evaluates password security by calculating information entropy and checking for common patterns, sequential characters, and length thresholds without transmitting secrets over the web.
Entropy
0 bits
Security Rating
Weak

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Copy this code snippet to add the Password Strength Checker to your blog or website for free. It adjusts dynamically to mobile and desktop screens.

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How to Use Password Strength Checker

Follow these steps to use the Password Strength Checker: 1. Type or paste your password string into the inspection box. 2. Observe the real-time security score and strength color indicator. 3. Check the calculation of password entropy bits displayed below. 4. Review the estimated time required for computers to crack the code. Enter your values to calculate the result instantly. This tool performs calculations locally in your browser.

Password Strength Checker Formula / How It Works

The tool calculates password entropy by assessing length and character pool options, checking values against common weak patterns.

Formula:Entropy = L * log2(R), where L is length and R is the size of the character pool.
Example Calculation:

For example, let's look at entering the password string "p@ssword123" into the checker. By entering these values into the tool, you will get a "Weak" strength rating, low entropy, and an instant estimated crack time instantly.

Frequently Asked Questions

A measurement of a password’s randomness and resistance to brute-force guessing attacks.

A simple 8-character password can be cracked instantly; a strong 16-character password would take millions of years.

Absolutely not. All checks run client-side inside your browser, ensuring no data leaks.

Passwords containing names, dictionary words, sequences like "123456", or keyboard paths like "qwerty".

Adding characters increases entropy exponentially, while adding character sets only increases it linearly.

More tools available in our full calculator directory.