Data breaches happen constantly — thousands every year — and most people have no idea their passwords are already exposed online.
Attackers don’t “guess” passwords anymore. They simply download leaked databases and try those passwords everywhere.
This guide shows you how to check if your email or password has been leaked safely, without exposing the password again, and what to do if you discover a breach.
Why Leaked Passwords Are So Dangerous
Once a password appears in a breach, attackers:
- add it to massive credential-stuffing lists
- try it on social media, banking, email, and cloud accounts
- use automated bots to test millions of accounts at scale
If you reuse the same password anywhere, a single breach can compromise multiple accounts.
Checking for leaks is now essential.
Step 1: Check If Your Email Appears in a Data Breach
The safest way to detect leaks is by checking whether your email address appears in known breach databases.
Trusted services like Have I Been Pwned allow you to check your exposure without uploading any passwords.
If your email appears in one or more breaches, it’s a strong signal that passwords associated with that email were also leaked at some point.
Step 2: Check If Your Password Has Ever Been Leaked (Safely)
Never paste your real password into random websites — many are outright scams.
Use tools that perform a k-anonymity check, meaning your password is transformed into a cryptographic hash, and only a small, anonymous part of that hash is checked against breach lists.
Our own Password Strength Checker and hashing tools let you generate secure replacements without ever sending anything to a server.
If your password has been leaked, assume it is compromised everywhere you used it.
Step 3: If a Password Is Leaked, Change It Immediately
Follow these rules when updating accounts:
- Choose a brand-new, random password
- Make it at least 16 characters
- Do not reuse old patterns
- Use a password manager to store it
You can quickly create a secure replacement using the Free Password Generator or a long, random passphrase using the Passphrase Generator.
Step 4: Enable Multi-Factor Authentication (MFA)
Even a leaked password cannot be used if your accounts require an additional factor.
Prefer MFA methods such as:
- phone-based authenticators
- hardware keys (YubiKey, SoloKey)
- built-in passkey support
Avoid SMS if possible, but even SMS is better than nothing.
Step 5: Check for Reused Passwords
This is where real risk hides.
If you used the leaked password anywhere else — even years ago — change those accounts immediately.
Attackers use bots that test leaked passwords across hundreds of services:
- cloud storage
- banking
- social networks
- developer tools like GitHub
- Amazon / e-commerce
- forums and older accounts you forgot exist
Reusing leaked passwords is the #1 cause of account takeovers.
Step 6: Don’t Trust “Clever” Password Tricks
Attackers know every pattern people rely on:
- adding a ! at the end
- replacing a letter with a number
- simple variations of old passwords
- rotating between a few favorites
If a leaked password was “Coffee2023!”, changing it to “Coffee2024!” does not help.
Use strong, random passwords or real passphrases instead.
Step 7: Monitor for Future Breaches
Breaches are unavoidable.
What matters is catching them early and responding fast.
Use:
- breach alert services
- password manager alerts
- email monitoring tools
- security-focused browser notifications
Staying proactive prevents attackers from getting a head start.
Step 8: Use Local Tools for Maximum Privacy
Whenever you generate, inspect, or replace a password, prefer tools that run fully in your browser:
These rely on secure randomness (window.crypto) and never send your data anywhere.
Final Thoughts
Leaked passwords aren’t a matter of if — they’re a matter of when.
But with the right habits, a leak becomes a small inconvenience rather than a security disaster.
Remember:
- check breach data regularly
- replace any leaked password immediately
- never reuse passwords
- use MFA everywhere you can
- rely on strong, random passwords generated locally
Staying safe online is less about avoiding breaches and more about reacting correctly when they happen.