How to Check if Your Password Has Been Compromised (2026 Guide)
Over 900 million unique passwords have appeared in known data breaches. Most people have no idea their passwords are on that list until an account gets taken over. Here is how to check - and exactly what to do if yours is compromised.
What Is a Compromised Password?
A compromised password is one that has appeared in a known data breach dataset. When companies get hacked, attackers often steal their user databases - which contain usernames, email addresses, and passwords. Those databases get sold on dark web markets or leaked publicly. Security researchers collect these datasets and make them searchable so you can check if your credentials are in them.
A password being compromised does not always mean your specific account was accessed. It means that password is now known to attackers and is included in the wordlists they use for credential stuffing attacks - where they automatically try stolen passwords across thousands of websites to find accounts that reuse them.
This is why password reuse is so dangerous. One breach at a small forum you signed up for years ago can compromise your email, bank, and social media accounts if you used the same password everywhere.
The Problem With Most Password Checkers
Most free password breach checkers ask you to type your password into a form and send it to their server. Some hash the password first, some do not. Either way, you are trusting that server with your credential - the exact thing you are trying to protect.
This is not a theoretical concern. A tool marketed as a "security checker" that collects passwords is a significant risk. Even if the operator is trustworthy, their server could be breached, their logs could be subpoenaed, or their business could change hands.
The solution is k-anonymity - a model where your password never leaves your browser at all.
How K-Anonymity Works
K-anonymity was developed by Troy Hunt for the Have I Been Pwned API and is now the standard for safe password breach checking. Here is exactly how it works:
Using SHA-1 via the Web Crypto API, your browser converts your password into a hash string. This happens entirely on your device - no network request is made at this point.
Your browser sends only the first 5 characters of that hash to the Have I Been Pwned API. For example, if the full hash is A94A8FE5CC..., only 'A94A8' is transmitted.
The API returns all hash suffixes in its database that start with those 5 characters - typically hundreds or thousands of results. None of these reveal which specific password you are checking.
Your browser compares your full local hash against the returned list. If your hash suffix appears in the list, the password is compromised. The full hash and the full password never leave your device.
You can verify this yourself. Open DevTools in your browser, go to the Network tab, and watch the requests while checking a password. You will see one request to api.pwnedpasswords.com with a 5-character string. Nothing else.
Check your password now - no data collected
TrustScan's Password Compromise Checker uses k-anonymity - your password never leaves your browser. Also includes strength scoring, a password generator, and batch checking for up to 50 passwords.
Check Your Password Free →How to Check Your Passwords Step by Step
Check the passwords for your email, bank, and any account connected to payment information first. These are the highest-value targets and the most damaging if compromised.
Use TrustScan's Password Compromise Checker or the official HIBP password checker at haveibeenpwned.com/passwords. Both use k-anonymity so your password never leaves your browser.
A password not found in breaches can still be weak. Check both - breach status tells you if it is known to attackers, strength score tells you if it could be guessed or cracked.
If you use a password manager, export your passwords and run them through batch check mode. TrustScan's tool checks up to 50 passwords at once and exports results as CSV.
Do not prioritize - change all compromised passwords, not just the ones you think are important. Attackers use credential stuffing to try stolen passwords across thousands of sites automatically.
What to Do If Your Password Is Compromised
| Step | Action | Priority |
|---|---|---|
| 1 | Change the password on the affected site immediately | Do now |
| 2 | Change it on every other site where you used the same password | Do now |
| 3 | Enable two-factor authentication on the affected account | Do now |
| 4 | Check if the account shows any suspicious login activity | Do now |
| 5 | Set up a password manager so you never reuse passwords again | This week |
| 6 | Set up HIBP email notifications for future breach alerts | This week |
| 7 | Check other passwords you have used historically | This week |
How to Create Passwords That Won't Be Compromised
The goal is passwords that are both strong enough to resist cracking and unique enough that a breach at one site does not affect your other accounts.
A strong password is at least 16 characters, uses a mix of uppercase, lowercase, numbers, and symbols, and does not follow predictable patterns like words followed by numbers. An even better approach is a passphrase - four or more random words joined by hyphens, like correct-horse-battery-staple-42. Passphrases are easier to remember and just as strong as random character strings when they use enough words.
The only practical way to use strong, unique passwords everywhere is a password manager. It generates and stores a different password for every site. You only need to remember one master password. Bitwarden is free, open source, and works across all devices and browsers. It is the most recommended free option among security professionals.
TrustScan's Password Compromise Checker includes a built-in password generator for both random passwords and passphrases - so you can check your current password and generate a replacement in the same tool.
Set Up Ongoing Monitoring
Checking your passwords once is not enough - new breaches happen constantly. Subscribe to HIBP's free email notification service at haveibeenpwned.com/NotifyMe. You will receive an alert the moment your email address appears in a new breach - giving you the earliest possible warning to change affected passwords before attackers can use them.
Cybersecurity professionals building free privacy tools for the 2026 compliance landscape.