A password that "looks" complicated isn't always secure, and a long passphrase can be stronger than a short jumble of symbols. I7 Pixel's checker gives you the real numbers behind your password's security — instantly, with nothing ever leaving your browser.
From typing to actionable results in seconds.
A little know-how on how passwords actually get broken goes a long way toward choosing ones that hold up.
Entropy is expressed in bits, and each additional bit doubles the number of possible combinations an attacker has to try. A short password made only of lowercase letters can look "fine" but carries very low entropy, while a longer password mixing character types — or a passphrase of several unrelated words — carries dramatically more. Length generally matters more than complexity: a 16-character password of mixed real words often beats an 8-character jumble of symbols.
Online attacks are throttled by login rate limits, so they're slow — often thousands of guesses per second at most. Offline attacks against a stolen, properly hashed password database are far faster since there's no rate limit, though a slow hashing algorithm still helps. GPU-cluster attacks use specialised hardware to try billions of combinations per second, which is why weak or short passwords can fall in minutes once a database leaks. The same password can be "safe enough" in one scenario and trivially broken in another.
Attackers don't just brute-force random characters — they start with dictionaries of real words, leaked password lists, and common patterns like "123456", "qwerty", "password1", and keyboard walks. A password can have decent raw entropy on paper and still be one of the first things tried if it follows a predictable structure. Avoiding repeats, sequences, and dictionary words closes this gap and makes the crack-time estimates in this tool far more meaningful.
Quick guide to entropy ranges and where common password styles fall.
| Tier | Entropy Range | Typical Example |
|---|---|---|
| PIN (4 digits) | 0–14 bits | Numeric-only codes like a phone unlock PIN — crackable almost instantly offline |
| Simple (8 chars) | 14–36 bits | Short passwords with limited character variety, e.g. one word plus a number |
| Moderate (12 chars) Common | 36–60 bits | Mixed-case with numbers or symbols — reasonable for low-risk accounts |
| Strong (16 chars) Recommended | 60–80 bits | Long, mixed-character passwords or multi-word passphrases |
| Very Strong (20+) | 80+ bits | Randomly generated passwords — ideal for password-manager-stored credentials |
A quick strength check before you commit to a password can save serious trouble later — this tool covers every common scenario.
Answers to the most common questions about checking password strength with this tool.
Yes — completely free. There are no limits, no accounts, no watermarks, and no charges. Check as many passwords as you need.
No — never. All analysis happens entirely in your browser using JavaScript. Your password is never stored, logged, or transmitted anywhere, so you can even disconnect from the internet and the tool still works.
Entropy measures how unpredictable a password is, expressed in bits. Higher entropy means dramatically more possible combinations an attacker has to try, which directly increases how long a brute-force attack would take.
They're informed estimates based on standard attack speeds for online, offline slow-hash, and GPU-cluster scenarios. Real-world crack time varies with the target system's hashing algorithm and attacker resources, but the estimates are reliable for comparing relative password strength.
It flags common weaknesses such as repeated characters, sequential characters or numbers, keyboard walks, and dictionary words — predictable patterns that make a password easier to guess even if it looks complex at a glance.
Yes, for most accounts. A password manager lets you use a long, random, unique password for every site without needing to remember each one — which is far stronger than reusing memorable passwords across accounts.
All tools at I7 Pixel run in your browser — no uploads, no accounts, always free.