🕵️ Password Leak Checker
Check if your password has been exposed in data breaches. We check against 10+ billion leaked passwords from Have I Been Pwned.
100% Private & Secure
We use k-anonymity - your password is hashed locally and only the first 5 characters of the hash are sent to the API. Your actual password never leaves your device.
🌍 International Security Compliance
⚠️ CRITICAL SECURITY NOTICE:
- This tool follows NIST SP 800-63B international standards
- Compliant with ISO/IEC 27001 security requirements
- Meets GDPR and HIPAA data protection standards
- All processing happens locally in your browser (zero data transmission)
- Password analysis uses industry-standard entropy calculations
Note: Weak passwords detected by this tool are flagged based on global security research and breach databases.
🔍 How It Works
Hash locally: Your password is SHA-1 hashed in your browser
Send prefix: Only first 5 characters of hash sent to API
Compare locally: Check if full hash exists in results
This is called k-anonymity - ensures your password remains private!
📊 Data Source
Have I Been Pwned
Created by security expert Troy Hunt, HIBP contains:
- 10+ billion leaked passwords
- 700+ million unique passwords
- Updated regularly with new breaches
- Free API for password checking
Famous breaches included:
❓ Why Check Passwords?
- 🔓Credential Stuffing: Hackers test leaked passwords on other sites
- 📊Common Passwords: Millions use same weak passwords
- 💾Old Breaches: Your password might be leaked from forgotten accounts
- ⚡Fast Attacks: Leaked passwords are tried first
🛡️ If Password is Leaked
Immediate Actions:
- Change password on ALL sites using it
- Enable 2FA (two-factor authentication)
- Check for unauthorized account activity
- Use a password manager
Prevention:
Use unique passwords for each site with ourPassword Generator
📈 Breach Statistics
🛡️ Understanding Password Leaks and Data Breaches
In today's digital landscape, data breaches have become alarmingly common. Major companies, social media platforms, and service providers regularly fall victim to cyberattacks that expose millions, sometimes billions, of user credentials. When these breaches occur, passwords and other sensitive information are often leaked onto the dark web or publicly shared databases, making them available to cybercriminals who use them for credential stuffing attacks, identity theft, and unauthorized account access.
A password leak occurs when your password appears in a database of compromised credentials from a data breach. Even if you haven't directly been affected by a breach, if you've reused passwords across multiple services, a breach at one company could compromise your accounts elsewhere. This is why password reuse is one of the most dangerous security practices—a single breach can cascade across all your accounts.
The scale of password leaks is staggering. According to security research, over 11 billion accounts have been compromised in data breaches, with passwords from major companies like Yahoo, LinkedIn, Adobe, and many others circulating on the dark web. These leaked passwords are often sold, traded, or shared freely among cybercriminals, creating an ongoing threat to anyone whose credentials have been exposed.
Our password leak checker uses the Have I Been Pwned database, which aggregates data from hundreds of publicly known data breaches. This database contains over 10 billion leaked passwords, making it one of the most comprehensive sources for checking if your password has been compromised. The service uses advanced security measures to protect your privacy while checking for leaks.
The most critical aspect of password leak checking is privacy protection. Our tool uses k-anonymity, a privacy-preserving technique that ensures your full password never leaves your device. Instead, only the first 5 characters of your password's SHA-1 hash are sent to the service, which then returns a list of all password hashes that start with those characters. Your browser then checks if your password's hash is in that list, all without revealing your actual password.
If your password appears in a leak database, it means that password is known to attackers and should be changed immediately on all accounts where you've used it. Even if the leak is from an old breach, the password remains dangerous because attackers maintain and use these databases for years. Changing leaked passwords is one of the most important steps you can take to protect your online accounts.
📖 How to Check if Your Password Has Been Leaked
Checking if your password has been leaked is simple and secure:
- Enter Your Password: Type the password you want to check in the input field. You can toggle visibility to ensure you've entered it correctly.
- Click Check Password: The tool will hash your password using SHA-1 and send only the first 5 characters of the hash to the Have I Been Pwned service. Your full password never leaves your device.
- Review Results: The tool will tell you if your password has been found in any known data breaches. If found, it will show how many times the password has appeared in breaches.
- Take Action: If your password has been leaked, change it immediately on all accounts where you've used it. Generate a new, strong, unique password using our password generator.
Privacy Note: Our tool uses k-anonymity protection, meaning only a partial hash is sent to the service. Even the service provider cannot determine your actual password from the information sent. This ensures complete privacy while still allowing you to check if your password has been compromised.
💼 When to Check Your Passwords
After a Data Breach Announcement
When a company announces a data breach, check all passwords you've used with that service. Even if the company says passwords were hashed, check them anyway—many breaches involve weak hashing or complete password exposure.
Before Reusing Passwords
Before reusing an old password on a new account, check if it has been leaked. If it has, generate a new password instead. This prevents attackers from using leaked credentials to access your new account.
Regular Security Audits
Periodically check your important passwords, especially those for email, banking, and social media accounts. Even if you haven't heard of a breach, your password may have been leaked from a breach that wasn't publicly disclosed.
When Setting Up New Accounts
Before using a password for a new account, check if it's been leaked. This ensures you're not starting with a compromised password, which would put your new account at risk from day one.
✅ Protecting Yourself from Password Leaks
1. Use Unique Passwords Everywhere
Never reuse passwords across multiple accounts. If one account is breached, reused passwords allow attackers to access all your other accounts. Use a password manager to generate and store unique passwords for each service.
2. Change Leaked Passwords Immediately
If a password check reveals your password has been leaked, change it immediately on all accounts where you've used it. Don't wait—attackers actively use leaked password databases, and delay increases your risk of compromise.
3. Enable Two-Factor Authentication
Even if your password is leaked, two-factor authentication (2FA) provides an additional layer of protection. Attackers would need both your password and access to your authentication device to breach your account.
4. Monitor Your Accounts
Regularly review your account activity for suspicious logins or unauthorized access. Many services provide login history and security alerts—enable these features and review them regularly.
5. Use Strong, Complex Passwords
Strong passwords are less likely to be cracked even if they're leaked. Use our password generator to create long, complex passwords with a mix of characters. Longer passwords (16+ characters) are exponentially more secure.
6. Check Passwords Regularly
Make password leak checking part of your regular security routine. Check important passwords every few months, and always check passwords after hearing about major data breaches in the news.