Tool · Password strength
Check password strength
Check your password strength in real time – entropy score, weakness detection and realistic crack time. Runs entirely in your browser.
Type a password to check its strength
How to build a genuinely strong password
- At least 14 characters – even better, a passphrase of 4–5 words.
- Mix uppercase, lowercase, digits and symbols.
- No names, birthdays, hobbies or "123" – attackers try those first.
- A unique password per account. Impossible manually, hence: password manager.
Privacy: everything stays in the browser
This checker makes no network requests. Your password is computed exclusively locally in your browser – nothing is sent to our server, Google, Facebook or any third party. You can simply close the page afterwards.
Methodology
Scoring is based on Shannon entropy (length × log2(charset size)) minus heuristic penalties for common weaknesses such as dictionary hits, sequences, repeats, years and "name+number" patterns. The crack time assumes a modern offline attack at 10 billion guesses per second – realistic for current GPU clusters.