Password Strength & Breach Checker

What is a Password Strength Tester and Why Do You Need It?

The strength meter looks at characteristics such as length and predictability. The optional breach lookup uses Have I Been Pwned data to check for matches; the service cannot identify every exposed password.

The strength meter estimates password characteristics, while the optional breach lookup checks for a match in Have I Been Pwned data. A match is useful to know, but no match cannot confirm that a password has never been exposed.

Why Use a Password Breach Checker and Strength Meter?

1. Know If Your Password Has Been Leaked

The optional breach lookup checks a password hash prefix against the Have I Been Pwned range API. A match means the password appears in that provider's data; no match does not prove a password has never been exposed.

2. Estimate Cracking Time

The page displays a rough time estimate based on an assumed guessing rate. Actual guessing depends on the attacker and the target protections, so treat the estimate as an illustration rather than a prediction.

3. Generate a Strong, Unpredictable Password

The page includes a convenience generator, but it uses the browser's general purpose random function rather than a cryptographic random source. Do not rely on its output for important accounts; use a trusted password manager generator instead.

4. Educate Yourself on Password Best Practices

Long, unique passwords are harder to guess and help limit the effect of a password exposed by one service.

How Our Password Strength & Breach Checker Works

The strength estimate runs locally. The optional breach check makes an external request with a partial password hash.

1. Type or paste a password – The strength meter updates in real time, showing entropy, crack time, and a percentage score.
2. Wait a moment – After you stop typing, the tool automatically checks the password against the HaveIBeenPwned breach database (requires at least 4 characters). Only the first five characters of the SHA‑1 hash are sent, keeping your password confidential.
3. Review the results – You’ll see if the password has ever been leaked, along with how many times. If it’s weak or breached, generate a new one instantly using the “Generate Strong” button.

The full password is processed by this page's JavaScript for the local estimate. The breach lookup sends a partial hash to an external service, so do not enter a password currently used on an important account.

When Should You Use a Password Breach Checker?

• Creating a new account – Test your chosen password before you commit. Make sure it’s strong and hasn’t been leaked.
• After a data breach announcement – If a website you use was hacked, check if your password for that site is now public.
• Regular security audits – Periodically test passwords stored in your password manager to identify weak or compromised ones.
• Helping friends and family – Share the tool to help others avoid common password mistakes.

Frequently Asked Questions About Password Strength & Breach Checks

What is a good password strength score?

The displayed score is a heuristic from this tool, not a guarantee of security or a reliable estimate of time to guess. Prefer a unique, randomly generated password stored in a password manager.

Is it safe to use an online password checker?

The full password is not sent to the breach lookup service, but the first five characters of its SHA-1 hash are. The local strength estimate also processes the password in this page. Avoid testing a password that protects an important account.

What does “Time to crack” mean?

Guessing time depends on the password, attacker, target protections, and many other assumptions. Treat any time shown as a rough illustration, not a prediction.

How accurate is the breach database?

The tool queries Have I Been Pwned's breach range service. It can only report matches represented in that service; no breach lookup covers every exposed credential.

Can I check passwords for free?

Yes. No account is required to use the strength meter or request a breach lookup.

Should I change my password if it has been breached?

A match is a reason to change the password promptly, especially if you still use it. A match means it appears in the breach data checked by this tool; it does not establish who has accessed it. Replace it with a unique password and do not reuse it across sites.