Password Strength Checker
Test your password strength and security. Get instant feedback, strength score, estimated time to crack, and personalized recommendations to improve your password security. All checks happen in your browser - your password never leaves your device.
What Makes a Strong Password?
A strong password is your first line of defense against unauthorized access to your accounts. It should be long, complex, unique, and unpredictable. Strong passwords combine multiple character types and avoid common patterns or dictionary words. The goal is to make it computationally infeasible for attackers to guess or crack your password.
Essential Password Characteristics
Minimum 12 characters. Each additional character exponentially increases security. 16+ is excellent.
Combine uppercase, lowercase, numbers, and symbols. Increases possible combinations dramatically.
No dictionary words, common phrases, personal info, or simple patterns like "123456" or "qwerty".
Use different passwords for each account. One compromised password shouldn't affect all accounts.
Password Strength Levels
| Strength | Score Range | Characteristics | Time to Crack |
|---|---|---|---|
| Very Weak | 0-20 | Short, simple, common patterns | Instant to seconds |
| Weak | 21-40 | Short with some complexity | Minutes to hours |
| Fair | 41-60 | Moderate length and complexity | Days to weeks |
| Good | 61-80 | Good length with mixed characters | Months to years |
| Strong | 81-100 | Long, complex, unpredictable | Centuries+ |
Common Password Mistakes to Avoid
- Using personal information: Names, birthdays, addresses, phone numbers are easily guessable
- Dictionary words: Any word found in dictionaries can be cracked quickly
- Simple substitutions: "P@ssw0rd" is still weak - hackers know common substitutions
- Sequential patterns: "123456", "abcdef", "qwerty" are among the most common passwords
- Reusing passwords: Same password across sites means one breach compromises all accounts
- Short passwords: Anything under 12 characters is vulnerable to brute force attacks
- Common phrases: "iloveyou", "letmein", "welcome" are too predictable
- Keyboard patterns: "qwertyuiop", "asdfghjkl" follow keyboard layout
- Year patterns: Adding year at end like "Password2024" doesn't help much
- All same character type: All lowercase or all numbers lacks complexity
How Password Cracking Works
Attackers use various methods to crack passwords. Understanding these helps you create stronger passwords:
Brute Force Attack
Tries every possible combination systematically. A 6-character password with only lowercase letters has 308 million combinations - modern computers can try billions per second. Length is your best defense.
Dictionary Attack
Uses lists of common words, phrases, and previously leaked passwords. This is why dictionary words and common passwords are weak even if they're long.
Rainbow Table Attack
Uses precomputed hash tables to reverse cryptographic hash functions. Salting and modern hashing algorithms help defend against this.
Best Practices for Password Security
- Use a password manager: Generate and store unique, strong passwords for each site
- Enable two-factor authentication (2FA): Adds extra security layer beyond password
- Create passphrases: 4-5 random words can be both secure and memorable
- Never share passwords: Don't share via email, text, or write them down insecurely
- Change compromised passwords immediately: If a service is breached, change that password
- Avoid password hints: They often make passwords easier to guess
- Use biometrics when available: Fingerprint or face unlock adds convenience and security
- Regular security checkups: Review and update passwords periodically
- Be wary of phishing: Never enter password on suspicious sites or emails
- Use secure password recovery: Set up recovery email and phone carefully
Understanding Password Entropy
Entropy measures the randomness and unpredictability of your password. Higher entropy means more secure. It's calculated based on the character set size and length.
Entropy = log₂(R^L)
L = Length of password
Result = Bits of entropy (higher is better)
8 lowercase letters: ~37 bits (weak)
12 mixed characters: ~71 bits (good)
16 mixed with symbols: ~105 bits (excellent)
Password Creation Strategies
The Passphrase Method
Create memorable yet secure passwords using random words:
4 random words + number + symbol = Strong & Memorable
- Choose 4-5 truly random words (not a sentence)
- Add numbers and symbols for extra strength
- Use separators (hyphens, spaces, underscores)
- Easy to remember, hard to crack
Frequently Asked Questions
How long should my password be?
Minimum 12 characters for general use. 16+ characters for high-security accounts like banking or email. Each additional character exponentially increases security.
Should I use a password manager?
Yes! Password managers generate strong, unique passwords for each site and remember them for you. They're more secure than reusing passwords or using weak ones you can remember. Popular options: 1Password, Bitwarden, LastPass, Dashlane.
How often should I change my password?
Change immediately if you suspect compromise or after a known breach. Otherwise, focus on using strong, unique passwords rather than frequent changes. Forced frequent changes often lead to weaker passwords.
Is "P@ssw0rd!" a strong password?
No. Despite having uppercase, lowercase, numbers, and symbols, it's based on a common word and uses predictable substitutions. Attackers' dictionaries include these variations. Choose something unpredictable instead.
What is two-factor authentication (2FA)?
2FA requires a second form of verification beyond your password - like a code from your phone, biometric scan, or security key. Even if someone gets your password, they can't access your account without the second factor. Enable it wherever possible.
Is my password sent to your server?
No! All password checking happens entirely in your browser using JavaScript. Your password never leaves your device and is not stored, logged, or transmitted anywhere. This tool is completely private and secure.