How to Check Password Strength and Crack Time

To check your password strength, paste it into a strength checker and read three things: the entropy in bits, the estimated crack time, and the warnings about weak patterns — higher entropy and a longer crack time mean a stronger password. A good checker does this without ever sending your password anywhere. Here is how to run the test and, more usefully, how to read what it tells you.

What the checker measures

Password strength comes down mainly to entropy, expressed in bits. Entropy grows with the size of the character set you use — lowercase, uppercase, digits and symbols — and, far more importantly, with length. The tool calculates this, then translates it into a five-level strength rating and an estimated time for a fast offline attacker to brute-force it. It also scans for weaknesses that raw length hides, like dictionary words, repeated characters and keyboard runs such as qwerty, and lowers the effective score when it finds them.

Step by step

1. Type or paste the password you want to test into the box.
2. Toggle "Show password" if you want to confirm exactly what you entered.
3. Read the strength rating alongside the entropy in bits and the estimated crack time.
4. Review the warnings about patterns, repeats and common words — these explain any gap between length and strength.
5. Apply the tips and watch the score update live as you edit, so you learn what each change is worth.

Reading the numbers

The entropy figure is the honest core of the result. Use this rough guide to interpret it rather than trusting a vague label alone:

Entropy (bits)	Rating	Verdict
Under 40	Weak	Change it
40-60	Fair	Acceptable for low stakes
60-80	Strong	Good for most accounts
Above 80	Very strong	Suitable for high-value logins

Treat the crack-time estimate as a relative guide, not a promise. It assumes a fast offline attacker hammering a stolen hash at a set number of guesses per second; real times swing widely with the hashing algorithm and hardware. What matters is the direction: adding length reliably pushes the estimate up, while a dictionary word drags it down.

Why testing in-browser is safe

You should never type a real password into a site that might transmit it. This checker analyses everything locally in your browser with JavaScript — nothing is uploaded, stored or logged — and it keeps working with your network disconnected, since it is a PWA. That is what makes it safe to test the passwords you actually use, rather than made-up samples that tell you nothing about your real accounts.

Try the Password Strength Checker — free and 100% in your browser.

FAQ

Is it safe to type my real password here?

Yes. All analysis runs locally in your browser and nothing is transmitted or saved. The tool even works offline, so your real password never leaves your device.

What entropy score should I aim for?

Aim for at least 60 bits for everyday accounts and above 80 bits for high-value logins like email and banking. A long random passphrase reaches these levels easily.

Why is my long password still rated weak?

Length helps only if the characters are unpredictable. If your password contains a dictionary word, a keyboard run or heavy repetition, the checker lowers the effective strength because attackers try those first.

How reliable is the crack-time figure?

It is an informed estimate, not a guarantee. Use it to compare passwords and to see the effect of changes, rather than as an exact number of years.

Related free tools

• Passphrase Generator — create a strong, memorable phrase to test here.
• Password Generator — build random high-entropy passwords.
• Secure Token Generator — generate tokens and keys.
• Random PIN Generator — make secure numeric PINs.

Built by ByteVancer

ByteTools is a free product of ByteVancer, a software and web development studio building web apps, SaaS and custom software. If you rely on fast, private security tools, explore what ByteVancer can build for your team.