Pwned Password Leak Checker Guide
Check if your password was exposed in public data breaches using 100% private client-side k-anonymity SHA-1 hashing.
Overview
Verify whether a password has appeared in historical data breaches using mathematical k-anonymity. Your password is hashed with SHA-1 on your device and never sent across the network.
When to Use Pwned Password Leak Checker
Use Pwned Password Leak Checker before adopting a new password or when auditing company credential policies.
Inputs, Formats & Specifications
- Accepted Inputs
- Password text string
- Output Formats
- Breach status (Clean or Compromised), exact breach occurrence count, SHA-1 prefix disclosure
- Supported Standards
- UTF-8 string, SHA-1 160-bit hash, k-Anonymity API (v3)
- Browser Limits & Scope
- Checks presence in known, cataloged public data breaches; zero breach records does not guarantee a password cannot be guessed if it is too short.
How to use Pwned Password Leak Checker
- Type or paste a prospective password into the secure password search field.
- The tool calculates the SHA-1 hash of your password locally in your browser.
- Only the first 5 characters of the hash prefix are queried against the Have I Been Pwned API.
- The browser inspects the returned hash suffixes locally to tell you if the password was leaked, and how many times.
Real-World Examples
Frequently Asked Questions
Is it safe to type my password here?
Yes. This tool uses mathematical k-anonymity: your password is SHA-1 hashed client-side in your browser. Only the first 5 characters of the hash are queried. The plain text password never leaves your browser.
What should I do if my password was found?
If your password was found in breach databases, immediately change it on any active service where it is used, and adopt a unique, high-entropy password.
What is k-anonymity?
k-Anonymity is a cryptographic privacy model where you only reveal a tiny fragment of a hash prefix. The server sends back hundreds of matching possibilities, and your browser does the final matching locally.
Privacy & Data Security
Pwned Password Leak Checker queries verified public open data directly from your browser with zero tracking and zero API keys.