Is it safe to paste my password here?

The tool hashes your password locally with SHA-1 and sends only the first 5 characters of that hash — this is the k-anonymity design used by security professionals. Your full password can never be reconstructed from what is sent.

Password Breach Checker

Check whether a password has appeared in known data breaches using the k-anonymity API — only a short hash prefix is ever sent, so the password itself never leaves your device.

100% free No uploads Runs in your browser No signup

Password breach checker

Password

Only the first 5 characters of its SHA-1 hash are sent — the password itself never leaves your device (k-anonymity).

How it stays safe: your browser hashes the password with SHA-1, then sends only the first 5 hash characters to api.pwnedpasswords.com. The service returns a few hundred hash suffixes matching that prefix, and your browser compares locally — the k-anonymity protocol used by security professionals. The full hash (let alone the password) never leaves this page.

How to use the Password Breach Checker

1
Open the tool above — it is already running, no install or account needed.
2
Enter your input and adjust the options to match what you need.
3
Copy or download the result — everything was processed locally in your browser.

Private by design

This tool runs 100% inside your own browser using local JavaScript — your input never touches a server. That makes it instant, offline-capable in many cases, and private even for sensitive data.

Frequently asked questions

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