Password Breach Checker — Leaked-Password Lookup, Privately

Find out if a password shows up in billions of breached credentials — your actual password never leaves this page.

Quick answer: Check if your password appeared in known data breaches — without ever sending it anywhere. Uses the Have I Been Pwned database with k-anonymity: only the first 5 characters of a hash leave your browser.

Password to check

How to use

Type the password you want to check (it is hashed in your browser first).
Press Check — only 5 hash characters are sent to the API.
If it appears in breaches, stop using it and generate a new unique password.

About this tool

Billions of passwords leak in breaches every year and get reused. This checker queries the famous Have I Been Pwned password database the same privacy-first way HIBP itself does: your password is hashed with SHA-1 inside your browser, only the first 5 characters of that hash are sent to the API, and the matching is finished locally. Not even we could reconstruct your password from what is transmitted — that is what k-anonymity means. If the password shows up in breaches, retire it immediately and use our Password Generator to make a unique one.

FAQ

Does the site see my password?

No. The password is SHA-1 hashed in your browser; only the first 5 hex characters of the hash are sent, which cannot be reversed into your password.

What database is used?

Troy Hunt's Have I Been Pwned — the industry-standard collection of breached credentials, free for exactly this k-anonymity check.

Why SHA-1 if it's broken?

SHA-1's collision weakness doesn't matter here — the database is indexed by it and pre-images still can't be recovered from 5 hex chars.

My password wasn't found — am I safe?

It's not in this database, but reuse is still risky: use a unique password per site.

Should I check my work passwords?

Check them here safely, but ideally use a password manager and rotate anything old.

Is checking free?

Yes — the Pwned Passwords API is free for this privacy-preserving range lookup.

Rate this tool

Your rating stays in this browser (local storage) — nothing is sent to any server.

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The complete password breach checker guide

Prefer the long version — a worked example, the mistakes people actually make, and answers to real questions? The blog guide Password Breach Checker — Complete Guide, Mistakes & FAQ covers all of it step by step.

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Password Breach Checker — Leaked-Password Lookup, Privately

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