Instant Password Check

How this password strength checker works

This tool uses zxcvbn, an open-source password strength estimator originally developed at Dropbox and now maintained by the open-source community. As you type, zxcvbn checks your password against a dictionary of 30,000+ common passwords, well-known patterns (keyboard sequences like "qwerty," dates, repeated characters, l33t substitutions), and calculates approximately how many guesses an attacker would need to crack it. The entire calculation runs client-side as a small JavaScript bundle — no part of your password is ever transmitted anywhere.

Is it safe to check my password here?

Yes — and you don't have to take our word for it. Open your browser's developer tools (press F12 in Chrome or Firefox, Cmd+Option+I on Mac), switch to the "Network" tab, and start typing in the password field above. You'll see exactly zero network requests fire per keystroke. That's not a promise we're making; it's something you can verify yourself, right now, in the browser you're using.

Many other password strength checkers send your password to a remote server for evaluation. Even when those services have good intentions, network logs, third-party analytics, server-side caching, and infrastructure providers can all see what gets transmitted. The only way to be certain your password is private is to never transmit it. That's what this tool does.

What makes a password strong?

Length matters more than complexity. A 16-character passphrase made of common words (like "correct horse battery staple") is exponentially harder to crack than an 8-character password with mixed cases and symbols (like "P@ssw0rd"). The reason is math: each additional character multiplies the number of possible combinations an attacker has to try — what cryptographers call entropy.

Three things make a password strong:

• Length. Aim for at least 12 characters; 16 or more is better.
• Unpredictability. Avoid common words, names, important dates, and keyboard patterns. zxcvbn is good at spotting all of these.
• Uniqueness. Never reuse passwords across accounts. If one site is breached, your other accounts stay protected.

How long would it take to crack my password?

The "estimated time to crack" displayed above assumes an attacker has obtained a leaked database containing your password's hash (the encrypted version that websites store) and is running brute-force guesses against it offline. We use the rate of 10,000 guesses per second, which roughly models modern slow-hashing algorithms like bcrypt or Argon2.

Against attackers with custom hardware — GPU clusters, ASIC farms, or nation-state resources — the rate can reach billions of guesses per second. A password that takes "centuries" against a typical attacker might fall in days against a well-resourced adversary. For the vast majority of threats most people face (credential stuffing, password reuse attacks, opportunistic data breaches), the 10,000-per-second benchmark is a reasonable estimate.

Why use a password manager

The honest truth: even a strong password isn't enough on its own. Every account you create needs a different password, because a single breach on a low-priority site shouldn't compromise your email, bank, or work accounts. Remembering 50+ unique strong passwords is impossible for humans — and writing them on sticky notes defeats the purpose.

That's what password managers solve. They generate random strong passwords for every site, store them encrypted with one master password (which you do need to remember), and fill them in automatically. Modern password managers like 1Password, NordPass, and Bitwarden use zero-knowledge architecture, meaning even the company that runs the service can't decrypt your passwords. The math is the same as what's running in this checker — the difference is that a manager remembers them for you.