What is the Password Strength Checker?
This tool measures how hard your password would be to guess. It gives a clear rating from “very weak” to “very strong”, a rough estimate of how long an attacker might need to crack it, and a checklist of what is missing. Everything runs inside your browser: the password is never sent to a server or stored.
How to use it
- Type the password in the field (tick “Show password” to see it).
- Watch the strength bar and the verdict update with every character.
- Read the checklist: every red item is a chance to make it stronger.
- Try small changes — for example adding two random words — and watch the score jump.
How is strength calculated?
We start from the entropy in bits: the length multiplied by the logarithm of the possible character set (lower case, upper case, digits, symbols). We then subtract points for the patterns attackers try first: sequences such as 1234, qwerty or azerty, repeats such as aaa, years such as 1995, and words from leaked-password lists even when letters are swapped for digits (P@ssw0rd).
| Scenario | Assumed speed |
|---|---|
| Online guessing (site limits attempts) | about 100 guesses per second |
| Cracking a leaked database with a powerful rig (fast hash) | about 10 billion guesses per second |
These figures are illustrative: real-world times depend on how the website stores passwords.
Practical tips
- Length beats complexity: 4–5 random words are stronger and easier to remember than a short complex string. Try the passphrase generator.
- One password per account: a breach on one site should not unlock the others. Use a password manager.
- Turn on two-step verification for email, banking and social media — it protects you even if a password leaks.
- Never type your real password on a site you don’t trust. Here you can verify it yourself: disconnect from the internet after the page loads and the tool still works.