What Is a Password Strength Checker?
A password strength checker estimates how hard a password is to guess or crack. Instead of trusting a vague rule such as “use a symbol”, PassGuard measures entropy – the number of guesses an attacker would need – and lowers the score when it spots weak patterns like qwerty, 123456 or P@ssw0rd. You see a clear 0–100 score, a crack-time estimate and specific advice to improve.
Why Password Strength Matters
Stolen and weak passwords drive a large share of account takeovers. Attackers use automated tools that try billions of guesses per second against leaked password databases, and they start with the most common choices and predictable variations. A short password such as summer2023 falls almost instantly, while a long random one can resist for centuries. Checking a password before you use it on email, banking or social media is one of the simplest security habits you can build.
How This Password Strength Checker Works
Entropy-based scoring
Entropy in bits equals the password length multiplied by log₂ of the character pool (lowercase 26, uppercase 26, digits 10, symbols about 33). Each extra bit doubles the work for an attacker. The checker then subtracts credit for repeated characters, sequences, keyboard walks and common words, so aaaaaaaaaaaa never looks strong just because it is long.
Score levels
| Entropy | Level | Meaning |
|---|---|---|
| Under 28 bits | Very weak | Cracked in seconds |
| 28–44 bits | Weak | Vulnerable to offline attacks |
| 45–62 bits | Fair | Fine only for low-value accounts |
| 63–80 bits | Strong | Good for most accounts |
| Over 80 bits | Excellent | Resists well-funded attackers |
Your privacy
All scoring happens locally in your browser. Nothing is uploaded, logged or saved. The optional Check breaches button uses the Have I Been Pwned k-anonymity service: your browser hashes the password with SHA-1 and sends only the first five characters of the hash, so the service never learns the password itself.
How to Create a Strong Password
Follow current NIST guidance
The NIST Digital Identity Guidelines favour length over forced complexity, recommend blocking known-breached passwords and advise against scheduled password changes without evidence of compromise.
Quick rules
- Use 14–16 or more characters, or a passphrase of 5–7 random words.
- Make every account’s password unique; reuse turns one breach into many.
- Avoid names, birthdays, pet names and dictionary words with simple substitutions.
- Use a reputable password manager and enable two-factor authentication.
- Generate passwords with the tool above – it uses your browser’s cryptographic random generator, not
Math.random().
Passphrase or random password?
A random password packs more entropy into fewer characters, which suits a password manager. A passphrase is easier to type and remember, which suits a device login or a manager’s master password. Add more words if you want more strength.
Common Password Mistakes
- Predictable substitutions: P@ssw0rd1 is on every cracking list.
- Keyboard walks: qwerty, asdfgh and 1q2w3e4r are tried first.
- Personal details: social profiles make names and dates easy to guess.
- Reusing one “strong” password: one breached site exposes all the others.
Explore more free utilities on floan.in, such as the file size converter and barcode generator. To see whether an email address appeared in a known breach, visit Have I Been Pwned.
Frequently Asked Questions
Is it safe to type my password into an online password strength checker?
Yes, when the analysis runs in your browser. PassGuard scores your password locally with JavaScript and never sends or stores it. The optional breach check sends only the first 5 characters of a SHA-1 hash, never the password. As a precaution, you can also test a similar password instead of your real one.
What makes a password strong?
Length and unpredictability. Aim for 14 or more random characters, or a passphrase of 5 to 7 unrelated words, and never reuse it on another account.
How is the password score calculated?
The score is based on estimated entropy in bits: length multiplied by the size of the character pool, reduced when the checker finds common passwords, keyboard walks, sequences or repeated patterns.
How often should I change my passwords?
NIST guidance recommends changing a password only when there is evidence of compromise, as long as it is long, unique and not already breached.
Are passphrases better than complex passwords?
A long random passphrase is easier to remember and can be as strong as a short complex password. Use more words for more strength, and store everything in a password manager.