Check whether a password appears in real-world data breaches — without the password ever leaving your browser. The check uses the k-anonymity method of the Have I Been Pwned database (860+ million leaked passwords): your password is fingerprinted locally, and only the first 5 characters of that anonymous fingerprint are sent. Nobody — not us, not the API — ever sees your password.
🔐 Password Leak Checker
✓ k-anonymity: the password never leaves this page
Tip: check old favourites you’ve reused for years — those are exactly the ones that show up with millions of hits.
How k-anonymity keeps this safe
Your browser computes a SHA-1 fingerprint of the password locally. It sends only the first 5 characters of that fingerprint to the Have I Been Pwned API, which returns every leaked fingerprint starting with those characters (typically 700–1,000 of them). The match is then found on your device. The API can never know which password — or even which full fingerprint — you were checking. This is the same mechanism password managers and browsers use for their breach warnings.
My password was found — how bad is it?
Treat it as public knowledge. Breached passwords go into “credential stuffing” lists that bots try against email, banking and shopping sites around the clock. Change it everywhere it’s used — starting with your email account, because email resets everything else. Then stop the cycle: a password manager generates and remembers a unique password per site, so one breach never opens a second door.
What makes a password strong in 2026?
Length beats complexity. A four-word passphrase (“coral-battery-window-taxi”) outperforms “P@ssw0rd1!” by orders of magnitude and is easier to remember. The full recipe: 12+ characters, unique per account, stored in a manager, with two-factor authentication (or passkeys, where offered) on anything important.
FAQ
Is it safe to type a real password here?
Yes — that’s the point of the k-anonymity design: the password and its full fingerprint stay on your device. If you’d still rather not, check a variation and apply the lesson to the real one.
What about checking if my email was breached?
Use haveibeenpwned.com directly for email lookups, then follow our digital footprint cleanup guide for what to do about the results.
“Not found” means my password is good?
It means it’s not in known leaks — a necessary condition, not a sufficient one. Short or guessable passwords (“Emma2019!”) can be cracked without ever having leaked.
