Check how strong your password really is. This analyzer evaluates entropy, pattern detection, common password lists, and estimated brute-force crack time - all locally in your browser.
Entropy measures the unpredictability of a password in bits. It is calculated as:
Where L = password length and R = size of the character set used.
Crack time assumes a brute-force attack at 10 billion guesses per second (modern GPU cluster). Real-world attacks using dictionaries and patterns may crack weak passwords much faster.
Type or paste a password into the input field to see an instant strength analysis. The tool evaluates multiple criteria: length, character diversity (uppercase, lowercase, numbers, symbols), common patterns (sequential characters, repeated characters, keyboard walks like 'qwerty'), and checks against a database of the most common passwords. A visual strength meter shows the overall score from 0 to 100, color-coded from red (weak) through orange and yellow to green (strong). Each criterion shows a pass/fail indicator so you can see exactly where your password falls short and how to improve it.
Password strength analysis is essential for security-conscious developers building registration forms who need to enforce password policies, system administrators auditing user passwords against compliance requirements (NIST, PCI-DSS), penetration testers evaluating password quality during security assessments, end users who want to verify their passwords before using them on important accounts, security awareness training to demonstrate the difference between weak and strong passwords, and QA testers validating that password strength meters in applications are working correctly.
The analyzer calculates Shannon entropy using the formula H = L * log2(R), where L is password length and R is the size of the character pool used (26 for lowercase, 26 for uppercase, 10 for digits, 32 for symbols). Crack-time estimation assumes 10 billion guesses per second (high-end GPU cluster) and divides the total keyspace (R^L) by the guess rate. Common password detection uses a built-in list of the top 100 most frequently used passwords. Pattern detection identifies sequential characters (abc, 123), repeated characters (aaa), and keyboard walks (qwerty, asdf). The tool follows NIST SP 800-63B guidelines which emphasize length over complexity.
A strong password is at least 12 characters long, uses a mix of uppercase, lowercase, numbers, and symbols, avoids dictionary words and common patterns, and is unique to each account. Length is the single most important factor - a 16-character passphrase like 'correct-horse-battery-staple' is stronger than a short complex password like 'P@ss1'.
Entropy measures the randomness of a password in bits. It's calculated as length × log2(character pool size). A password using only lowercase (26 chars) gets fewer bits per character than one using all ASCII printable characters (95 chars). Higher entropy means exponentially more guesses required to crack.
No. All analysis happens entirely in your browser using JavaScript. Your password never leaves your device, is never transmitted over the network, and is never stored anywhere. You can verify this by using the tool while disconnected from the internet.
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