Password Strength Checker

What Makes a Strong Password?

A strong password is your first line of defense against unauthorized access. Here's what makes a password strong:

Length matters most — Each additional character exponentially increases crack time. Aim for 12+ characters.
Mix character types — Use uppercase, lowercase, numbers, and special characters together.
Avoid common patterns — Don't use "password123", sequential numbers, keyboard walks (qwerty), or personal info.
Use unique passwords — Never reuse passwords across different accounts.
Consider passphrases — A random phrase like "correct-horse-battery-staple" is both strong and memorable.

How We Calculate Password Strength

Our password strength checker analyzes multiple factors:

Character pool size — The total possible characters based on types used (26 lowercase + 26 uppercase + 10 digits + 33 special = 95)
Entropy calculation — log2(pool_size^length) gives the number of bits an attacker must guess
Pattern detection — We check for common words, sequences, repetitions, and keyboard patterns that reduce effective entropy
Crack time estimation — Based on 10 billion guesses/second (modern GPU cluster capability)

Is this password checker safe to use?

Yes. This tool runs entirely in your browser using JavaScript. Your password is never transmitted over the internet, stored, or logged anywhere. You can verify this by checking the page source code or using your browser's network inspector.

How long should my password be?

At minimum 12 characters, but 16+ is recommended. Each additional character makes your password exponentially harder to crack. A 16-character password with mixed character types would take millions of years to brute-force.

Should I use a password manager?

Absolutely. A password manager lets you use unique, strong passwords for every account without memorizing them. Popular options include 1Password, Bitwarden, and KeePass.

What is password entropy?

Entropy measures the randomness (unpredictability) of a password in bits. Higher entropy means more possible combinations an attacker must try. A password with 80+ bits of entropy is considered very strong against current brute-force technology.

How fast can passwords be cracked?

Modern GPU clusters can test over 10 billion password combinations per second against common hash types. This is why short, simple passwords can be cracked in seconds, while long, complex ones would take millions of years.

Improvement Tips:

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