Breach lookup

Password Leak Checker

Find out whether a password already appears in public breach data — without ever sending the password itself.

Hashed in your browser. Only a five-character hash prefix is ever sent.

Overview

What is a Password Leak Checker?

A password leak checker tells you whether a password has already appeared in a public data breach. Modern attacks rarely involve guessing: attackers replay billions of previously exposed passwords against login forms, a technique called credential stuffing. If your password is on those lists, its length and complexity no longer matter.

This tool uses k-anonymity. Your password is hashed with SHA-1 inside your browser, and only the first five characters of the hash are sent to the lookup service. The service returns every hash sharing that prefix and the match is completed locally, so no one — including us — learns which password you checked.

Use cases

When to use it

Test a password before you start using it
Check old passwords you are about to retire
Confirm a reused password is safe to keep
Explain credential stuffing to a colleague
Validate a generated password against real leak data
Our Promise

How SafePasswordMaker Protects You

K-Anonymity Lookup

Only the first five characters of the hash ever leave your device.

Password Never Sent

Your actual password is never transmitted or stored.

Hashed Locally

SHA-1 hashing happens in your browser before any request.

Free & Unlimited

No sign-up, no rate cards, no logging.

Help

Frequently Asked Questions

Replace a leaked password now

Generate a long, unique password in your browser and store it safely.