Developer
7 min read
March 15, 2025

How to Create Strong Passwords That Hackers Can't Crack

'123456' is still the most common password in 2025. Here's the actual science of what makes passwords strong.

How to Create Strong Passwords That Hackers Can't Crack
PasswordCrack time
123456< 1 second
Password1~2 hours
P@ssw0rd!~3 days
correct-horse-battery~550 years
Random 16 chars~400,000 years

Password Entropy

Entropy (bits) = log₂(charset_size) × length

12-char full ASCII (95 chars): 6.57 × 12 = 78.8 bits. 80+ bits is considered strong.

NIST 2024 Guidelines

  • Minimum 15 characters (8 is no longer adequate)
  • Length beats complexity
  • Passphrases of 4+ random words are excellent
  • No forced periodic changes without evidence of compromise

    • CSPRNG vs Math.random()

    Our Password Generator uses crypto.getRandomValues() — never Math.random(). With CSPRNG, a 16-char password has 4.4 × 10³¹ possible values with no way to reduce the search space.

    After a Data Breach

  • Check haveibeenpwned.com — 12+ billion leaked credentials
  • Change the breached site password immediately
  • Enable two-factor authentication everywhere

    • Written by the GMC Tools team

    Try These Tools

    Password Generator

    Generate strong, secure passwords instantly

    Try free

    Random Number Generator

    Generate random numbers in any range

    Try free

    QR Code Generator

    Create QR codes for any URL or text

    Try free

    More Articles

    What Is JSON and Why Does Every App Use It?

    What Is JSON and Why Does Every App Use It?

    Almost every app on your phone sends and receives information using a format called JSON. Here's what it actually is, explained simply.

    What Is Regex (Regular Expressions) and How Does It Actually Work?

    What Is Regex (Regular Expressions) and How Does It Actually Work?

    Regex looks like a secret code, but it's really just a smart way of describing patterns in text. Here's how it works, explained simply.

    What Is Hashing and Why Is It So Important for Security?

    What Is Hashing and Why Is It So Important for Security?

    Ever wondered how websites store your password without actually 'knowing' it? The answer is hashing — a one-way digital fingerprint.