Password Strength Checker: Length, Variety, and Entropy Explained
Password advice often stops at strong or weak. This checker shows why, with length, character classes, and entropy side by side.
What is the Password Strength Checker?
A strong password is usually long and mixed, and this checker measures both qualities without ever saving or sending what you type. It counts length and the character classes present, estimates entropy from the size of the pool those classes imply, and turns the result into a simple rating. The advice stays practical: add length first, then mix in another character class if one is missing.
How to use it
- Type the password you want to check.
- Read the rating, length, and entropy estimate.
- Follow the single piece of advice shown.
- Check the new version again before you use it.
Worked example
Checking a long mixed password rates it very strong with a high entropy estimate.
What makes a password strong?
Length matters most, then variety. A long password drawn from lowercase, uppercase, digits, and symbols has a large entropy estimate, which means far more guesses are needed to find it.
Frequently asked questions
Is my password sent anywhere?
No. The check runs locally in the page, and nothing you type is stored or transmitted by this tool.
Does a high score guarantee safety?
No. A strong password still needs to be unique to one account, and reused passwords stay risky however complex they look.