OptiDrop

Password Strength Tester Advanced — Analyze Entropy & Crack Time Free

Get detailed password analysis including entropy bits, estimated crack time, character types, and improvement suggestions. Real-time analysis as you type. 100% free, no sign-up required.

Free Advanced Password Strength Tester Online

OptiDrop's Password Strength Tester is a free online tool that provides detailed analysis of your password security. As you type, the tool instantly calculates the password's entropy (measured in bits), estimates how long it would take to crack using brute force, identifies which character types are used, and provides a comprehensive strength score from 0 to 100.

Understanding Password Entropy

Entropy measures the randomness of a password in bits. It is calculated based on the password length and the size of the character pool (how many possible characters could appear at each position). A password using only lowercase letters has a pool of 26, while one using lowercase, uppercase, digits, and symbols has a pool of 95. More entropy means more possible combinations and a stronger password.

100% Private -- Runs in Your Browser

Your password is never sent to any server. All analysis happens locally in your browser using JavaScript. You can safely test any password without worrying about it being intercepted or recorded. The tool provides real-time feedback as you type, helping you create stronger passwords.

Frequently Asked Questions

Type a password into the input field and the tool analyzes it in real time. It checks the length, character types used (lowercase, uppercase, digits, symbols), calculates the entropy in bits, estimates the time it would take to crack the password using brute force, and gives a strength score from 0 to 100. It also provides specific suggestions to improve your password.
Password entropy is a measure of password strength expressed in bits. It is calculated based on the length of the password and the size of the character pool used. Higher entropy means more possible combinations, making the password harder to crack. A password with 60+ bits of entropy is generally considered strong, while 80+ bits is very strong.
Crack time is estimated by dividing the total number of possible password combinations by an assumed cracking speed. We use 10 billion guesses per second, which represents a modern offline attack with specialized hardware. The actual crack time depends on the attack method, hardware, and whether the password appears in known breach databases.
No. All password analysis happens locally in your browser. Your password is never sent to any server, stored, or logged. The tool runs entirely client-side using JavaScript. You can safely test any password without worrying about it being intercepted or recorded. 100% private and secure.

Last updated: June 2026