Password Strength Checker: How Secure Is Your Password?
Password security is one of the most important โ and most commonly misunderstood โ aspects of staying safe online. Most people know they shouldn't use password123, but fewer understand what actually makes a password resistant to attacks. Here's what you need to know.
What Makes a Password Strong?
Password strength comes down to two things: length and unpredictability. A longer password with random characters from a large set is exponentially harder to crack than a short password with substitutions like p@ssw0rd. Modern cracking tools know every common substitution pattern.
Length
HighEvery extra character multiplies the search space. 16 chars is much stronger than 12.
Character variety
HighMixing uppercase, lowercase, numbers, and symbols dramatically increases entropy.
Randomness
CriticalPredictable patterns (names, dates, words) reduce effective strength even if the password looks complex.
Uniqueness
CriticalReusing passwords means one breach exposes all your accounts. Every site needs its own password.
Understanding Password Entropy
Entropy measures how unpredictable a password is, expressed in bits. A password with 50 bits of entropy means an attacker would need to try 250 combinations on average to guess it. Each bit doubles the search space. A fully random 12-character password using upper, lower, digits, and symbols has around 78 bits of entropy โ far more than any humanly memorable word-based password.
Entropy comparison
password~18 bitsVery weakP@ssw0rd!~28 bitsStill weakcorrect-horse-battery-staple~44 bitsBetterxK#9mPqL2$rN~78 bitsStrongCommon Weak Password Patterns
- โข Dictionary words: Any word in any language is in cracking wordlists. Adding numbers at the end doesn't help much.
- โข Keyboard walks: Patterns like
qwerty,123456, orzxcvbnare among the first tried. - โข Personal info: Names, birthdays, pet names, or phone numbers are discoverable through social media or data breaches.
- โข Common substitutions: Replacing
awith@orewith3is well known to attackers. - โข Short passwords: Anything under 10 characters can be brute-forced in minutes with modern hardware.
Tips for Creating Strong Passwords
Use a password manager
Tools like Bitwarden, 1Password, or KeePass generate and store random passwords for every site. You only need to remember one master password.
Use passphrases for memorable passwords
A random sequence of 4โ5 uncommon words (not a famous phrase) is both memorable and strong. Add numbers and symbols for extra entropy.
Enable two-factor authentication
Even a weak password becomes much harder to exploit when 2FA is required. Use an authenticator app, not SMS, when possible.
Important: Don't use real passwords in online tools
Our password strength checker runs entirely in your browser โ nothing is sent to any server. But as a general habit, avoid typing real passwords into any online tool you don't fully trust. Use the checker with a similar-length test password to understand what makes yours strong or weak.
Check your password strength now
Entropy score ยท Crack time estimate ยท Private ยท Free ยท No sign-up
Open Password Strength Checker โFrequently Asked Questions
What makes a password strong?
A strong password has: at least 12 characters, a mix of uppercase and lowercase letters, numbers, and special characters (!@#$%^&*), and is not based on dictionary words, names, or dates. The longer and more random the password, the stronger it is.
How long should a password be?
Security experts recommend at least 12 characters as a minimum, with 16+ characters for sensitive accounts. A 12-character random password takes years to crack with modern hardware. A 20+ character passphrase (four random words like 'correct-horse-battery-staple') is both strong and memorable.
What is password entropy?
Password entropy measures the unpredictability of a password in bits. Higher entropy = harder to crack. A 12-character password using all character types (95 characters total) has about 79 bits of entropy. NIST recommends at least 112 bits for high-security applications.
Is it safe to check my password online?
You should never enter your actual passwords into online tools. Use a password strength checker only for test passwords or new passwords you're evaluating. Look for tools that run entirely client-side (no server) so your password never leaves your browser.
What are the most common weak passwords?
The most common weak passwords include: 123456, password, 12345678, qwerty, abc123, and variations of these. Personal info like birthdays, names, and pet names are also weak because they're predictable. Password managers generate and remember strong unique passwords for you.