Password Strength Checker

📖 Tool Introduction

Password Strength Checker helps you judge how secure a password really is before you commit it to an account. Instead of just counting characters, it uses the same information entropy model that security experts rely on. First it detects which character pools the password draws from: lowercase letters contribute twenty six, uppercase letters another twenty six, digits ten and printable symbols about thirty three. It then multiplies the combined pool size by the password length and takes the base two logarithm to arrive at an entropy value measured in bits. The higher that number, the more guesses a brute force attacker has to make on average. On top of the entropy score the tool runs a checklist of practical rules: whether the length clears eight characters and the stricter twelve character bar, whether both uppercase and lowercase letters appear, whether digits and symbols are mixed in, and whether any character repeats. It also recognizes famously weak choices like password, one two three four five six and qwerty, and applies an extra penalty so you do not get a false sense of safety. The final score from zero to one hundred is drawn as a colored semicircular gauge, with a plain language grade underneath, and every rule passes or fails with a visible check mark. Because every calculation happens inside your browser, the typed password is never uploaded, logged or shared, so you can safely paste real passwords and inspect them without hesitation. The advice panel then points you at the weakest link, suggesting a longer length, an added symbol or a mix of cases, so that one round of editing is enough to move from weak to strong.

✨ Key Features

• Entropy model: scores bits of entropy from pool size and length rather than a naive character count
• Semicircle gauge: the zero to one hundred score is drawn as a colored arc for instant visual reading
• Rule checklist: seven rules covering length, case, digits, symbols and repeats are ticked one by one
• Weak password detection: common phrases are recognized and penalized to avoid false confidence
• Actionable advice: missing rules produce concrete tips such as adding symbols or extending length
• Local only: passwords never leave the browser, with a show or hide plain text toggle

📝 How to Use

1. Paste or type the password you want to examine into the input field
2. Click the Show button to reveal plain text and confirm what you entered
3. Click Check Strength and read the score and grade on the semicircular gauge
4. Scroll through the rule checklist to see which items still fail
5. Follow the advice to edit the password, then check again until the score reaches Strong or above

⚠️ Notes

• Local analysis: every calculation runs in your browser, no password is sent to any server
• Reference only: the score measures resistance to brute force, not absolute safety, pair it with two factor authentication
• Length first: with the same character pool, extra length beats extra variety of character types
• Avoid common words: even a long password loses points if it contains strings like password or one two three four five six
• Clear after use: click the Clear button when you are done so the password is not left in the field