🛡️ Password Strength Checker

Real-time password security assessment from multiple dimensions including length, character composition, entropy estimation, brute-force time calculation, and common password detection.

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✖ Length ≥ 8 Password must be at least 8 characters

✖ Lowercase letters a-z

✖ Uppercase letters A-Z

✖ Contains numbers 0-9

✖ Special characters !@#$%^&* etc.

✖ Length ≥ 12 Bonus points

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Password Entropy (bits)

Password Length

📊 Character Composition Statistics

Upper

Lower

Numbers

Special

⏰ Brute Force Time Estimation

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Online Attack (Rate Limited)

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Offline Attack (GPU Accelerated)

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⚠ This password appears in the common passwords list and is extremely insecure! Do not use it.

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Enter a password to automatically check its strength

📝 Password Security Recommendations

Strong password criteria:
A secure password should meet the following requirements: at least 12 characters long; contains all four character types (uppercase letters, lowercase letters, numbers, and special symbols); does not contain common words, names, birthdays, or other personal information; does not match any known leaked passwords. Entropy of 60+ bits is considered secure, and 80+ bits is very secure.

What is password entropy?
Password entropy is a mathematical measure of password unpredictability, measured in bits. The higher the entropy, the harder the password is to brute-force. Each additional bit doubles the cracking difficulty. Formula: Entropy = Password Length × log₂(Charset Size). For example, a 12-character password containing uppercase letters, lowercase letters, and numbers has an entropy of approximately 71 bits.

Cracking time estimation notes:
Online attack assumes 10 attempts per second (limited by login rate restrictions). Offline attack assumes 10¹⁰ attempts per second (GPU-accelerated hash computation). Actual cracking time depends on factors such as attacker's computing power, hashing algorithm used (e.g., bcrypt/argon2 significantly slows down cracking), and more. This tool provides theoretical estimates for reference only.

Will my password leak?
No. All password checking and calculations run entirely in your browser locally. Passwords are never uploaded to any server. You can safely enter various passwords for security assessment.

Related guide

What the Password Generator and the Strength Checker Actually Compute
The generator rates your settings, the checker rates the string you type, and those two numbers are not comparable. Exact alphabet sizes (26/26/10/27), the four entropy bands, the 40-word common list, the crack-time model — plus the one unit label on the checker that is off by a factor of ten.