Password Strength Checker

Absolutely. This tool runs entirely in your browser using JavaScript. Your password never leaves your device — it is not sent to any server, stored in any database, or logged anywhere. You can verify this by disconnecting from the internet and using the tool offline.

Entropy is measured in bits and represents the number of possible combinations an attacker would need to try. It's calculated as log₂(pool_size^length), where pool size is the number of unique character types used (lowercase = 26, uppercase = 26, digits = 10, symbols = 33). A password with 60+ bits of entropy is considered strong.

Common weaknesses include: short length (under 10 characters), using only one character type, dictionary words, keyboard patterns like "qwerty", repeated characters like "aaa", predictable substitutions like "@" for "a" (l33t speak), and personal information like dates or names. Our checker detects all of these patterns.

Our estimates are based on two scenarios: brute force (trying every combination) at 10 billion guesses per second (modern GPU cluster), and dictionary/rule-based attacks at 1 billion guesses per second. Real-world times vary based on the attacker's hardware, but these give a realistic ballpark for a well-resourced attacker.

We recommend at least 14 characters using a mix of uppercase, lowercase, numbers, and symbols. Better yet, use a passphrase of 4–5 random words (20+ characters). Length is the single most important factor in password strength — each additional character exponentially increases the time needed to crack it.