# Password Strength Checker Measure how strong a password really is. See its entropy in bits, an estimated time-to-crack, and a set of actionable checks covering length, character variety and common weak patterns. Your password never leaves your device. ### How it works Strength is scored as Shannon entropy: the tool infers the character pool your password draws from (lowercase, uppercase, digits, symbols) and computes `length × log2(poolSize)` bits. That bit count is mapped to a crack-time estimate against a fast offline guessing rate, and to a plain-language rating from Very Weak to Very Strong. Additional checks flag short length, missing character classes and obvious sequences. All analysis is done locally in JavaScript — nothing is typed, logged or uploaded anywhere. --- *Source: [ocxly.com/password-strength-checker.html](https://ocxly.com/password-strength-checker.html) — OCXLY, free 100% client-side privacy-first tools. Free password strength checker — measure entropy in bits, estimate crack time and see actionable checks, entirely in your browser. Nothing is uploaded.*