list What You'll Learn
- What is Password Strength Analysis?
- How Our Analyzer Works (zxcvbn Algorithm)
- Understanding Strength Scores & Crack Times
- Password Entropy Explained
- Common Password Mistakes & Vulnerabilities
- Advanced Features: Breach Checking & Pattern Detection
- Practical Examples & Real-World Testing
- Password Creation Best Practices
What is Password Strength Analysis?
Password strength analysis is the process of evaluating how resistant a password is to being guessed or cracked by automated tools. It's not just about length or complexity—modern analysis considers dozens of factors that real attackers use.
Why It Matters:
Weak passwords are responsible for 81% of hacking-related breaches (2023 Verizon Report). A strong password is your first and often only line of defense against unauthorized access.
Our Password Strength Analyzer goes beyond basic "weak/medium/strong" ratings. It provides:
Advanced Algorithm
Uses Dropbox's zxcvbn algorithm that models real attacker behavior, not just simple rules.
Real Crack Time Estimates
Calculates how long it would take current hardware to brute-force your password.
Try It Now
Follow along with this guide using our live tool
How Our Analyzer Works: The zxcvbn Algorithm
Unlike basic checkers that just count characters, our tool uses Dropbox's open-source zxcvbn algorithm. Here's what makes it different:
| Feature | Basic Checkers | Our Analyzer (zxcvbn) |
|---|---|---|
| Pattern Detection | Basic sequences only | Advanced Keyboard patterns, l33t speak, dates |
| Dictionary Check | Common passwords only | 30,000+ words Multiple languages, names, sports terms |
| Entropy Calculation | Simple formula | Shannon entropy Context-aware calculation |
| Crack Time Estimate | Not provided | Real-time Based on current GPU capabilities |
The Analysis Process
Pattern Matching
The algorithm searches for common patterns: keyboard walks (qwerty, 12345), dates, repeating characters, l33t speak substitutions (p@ssw0rd).
Dictionary Attacks
Compares against 30,000+ common passwords, names, sports teams, and dictionary words in multiple languages.
Spatial Analysis
Detects keyboard spatial patterns and evaluates how "random" the password appears to be.
Entropy Calculation
Calculates Shannon entropy based on character pool size and password length.
Technical Deep Dive
zxcvbn uses a "most guessable match sequence" approach. It doesn't just check rules—it actually simulates how attackers guess passwords, considering human behavior patterns and common substitutions.
Understanding Strength Scores & Crack Times
Our analyzer provides a 0-100 score and estimated crack time. Here's what they mean:
Strength Score Breakdown
Crack Time Assumptions
Our estimates are based on:
- computer Hardware: Modern GPU (RTX 4090 equivalent)
- bolt Speed: 100 billion guesses/second for offline attacks
- security Hashing: bcrypt with cost factor 12
- warning Note: Online attacks are much slower (10 guesses/second)
info Tip: Aim for passwords that would take centuries to crack, even with future computing advances.
The 80/20 Rule of Password Security
80% of security breaches come from the 20% weakest passwords. Don't be in that 20%! Any password scoring below 60 should be changed immediately.
Password Entropy Explained
Entropy measures the randomness or unpredictability of a password. Higher entropy = harder to guess. It's measured in bits.
Entropy Calculation Formula
Entropy (bits) = log₂(Character Pool Size) × Password Length Where Character Pool Size = - 26 for lowercase only - 52 for lowercase + uppercase - 62 for letters + numbers - 94 for full keyboard (letters + numbers + symbols)
Example Calculations:
- "password" (8 lowercase) 37 bits
- "P@ssw0rd" (mixed) 52 bits
- "Tr0ub4dor&3" 66 bits
- "correct horse battery staple" 104 bits
Security Thresholds:
- ＜ 40 bits: Very weak (cracked instantly)
- 40-60 bits: Weak (cracked in days)
- 60-80 bits: Moderate (years)
- 80+ bits: Strong (centuries)
Why Passphrases Beat Complex Passwords
close Complex Password
Example: P@ssw0rd!2026
- close Hard to remember
- close Prone to predictable substitutions
- close Often written down
- close Entropy: ~65 bits
check Passphrase
Example: correct-horse-battery-staple
- check Easy to remember
- check Resistant to dictionary attacks
- check Can be spoken aloud
- check Entropy: ~100+ bits
Try It Yourself: Interactive Examples
Test these passwords in our analyzer to see real results:
password123
Expected: Very Weak (0-20)
Summer2026!
Expected: Weak (21-40)
BlueElephant@99
Expected: Strong (61-80)
Common Password Mistakes & Vulnerabilities
Predictable Substitutions
Replacing letters with similar-looking symbols doesn't fool modern crackers.
p@ssw0rd is just as weak as password
Modern cracking tools automatically try these substitutions. They're in every hacker's dictionary.
Keyboard Patterns
Sequential keys are incredibly common and easily guessed.
qwertyuiop • 12345678 • 1qaz2wsx
These are literally the first combinations attackers try. Don't walk your fingers across the keyboard.
Personal Information
Using names, birthdays, or pet names makes passwords guessable.
Jessica1990 • Fluffy123 • BostonRedSox
Social media makes this information public. Attackers gather it automatically.
Pro Tip: Check for Breaches
Use our analyzer's "Check Against Breach Database" feature. Even strong passwords are useless if they've been leaked in a data breach. We check against Have I Been Pwned's database of 613 million breached passwords.
Advanced Features: Beyond Basic Analysis
Our Password Strength Analyzer includes professional features used by security teams:
Breach Database Check
Checks password against 613+ million known breached passwords using secure hashing (k-anonymity).
- check Uses Have I Been Pwned API
- check Your password never leaves your browser
- check Shows how many breaches it appears in
Pattern Detection
Identifies specific weaknesses in your password structure.
- check Keyboard walks and sequences
- check Repeating characters
- check Dictionary words with substitutions
- check Dates and years
Password History & Comparison
Professional feature: Compare multiple passwords to find the strongest option.
Password Creation Best Practices
The 5 Golden Rules
Length Beats Complexity
A 16-character lowercase password has more entropy than an 8-character mixed password. Aim for at least 12 characters, preferably 16+.
Use Passphrases
Combine 4-6 random words: "correct-horse-battery-staple". Add numbers/symbols if required: "Correct-Horse-7-Battery-Staple!"
Be Unique & Random
Each site gets a unique password. Use our Password Generator tool for truly random passwords.
Check Before Use
Always test new passwords in our analyzer. Aim for a score of 80+ and crack time of "centuries".
Use a Password Manager
Let tools like Bitwarden or 1Password generate and store strong, unique passwords for every site.
Password Strength Checklist
✅ DO:
- check_circle Use 12+ characters (16+ for critical accounts)
- check_circle Create unique passwords for every site
- check_circle Use passphrases with random words
- check_circle Enable 2FA wherever possible
❌ DON'T:
- cancel Use personal information
- cancel Reuse passwords across sites
- cancel Use keyboard patterns
- cancel Write passwords on paper
Ready to Secure Your Passwords?
Start using our advanced Password Strength Analyzer today. It's free, private, and used by security professionals worldwide.
Next: Read our guide on Password Managers: Complete Guide