Password Strength Checker With Entropy Score

Check password strength with an entropy-based score and tips.

Most password meters reward a single exclamation mark and call the job done. This checker scores passwords on entropy, a measure of how many guesses an attacker would need on average, based on length and the mix of character types. Type a password and it returns a rating, a bits score, and concrete tips for making it stronger. The check runs entirely in your browser, so the password you test never leaves your device.

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About Password Strength Checker

Most password meters are glorified guesswork, they reward a single exclamation mark and call it a day. This checker scores passwords on entropy: a real measure of how many guesses an attacker would need on average, driven mostly by length and character variety. Type a password in and you get a visual meter, a rating, and concrete tips for making it stronger.

Length is the dominant factor, which surprises people. Adding a few more characters beats swapping letters for symbols almost every time, and avoiding common words and keyboard patterns, names, years, "password123," qwerty walks, matters more than satisfying a site's checkbox rules. The check runs 100% in your browser, with nothing sent, stored, or logged, so it's safe to test the actual password you're considering.

Keep two caveats in mind. First, a strong score measures guessing resistance, not overall safety: a "very strong" password that's reused across ten sites or handed to a phishing page is still compromised, pair unique passwords with a password manager. Second, no score can promise a password can't be cracked; it estimates the effort required, not impossibility. Use the rating as guidance, then generate and store something better if it falls short.

Worked example: a 12-character password using lowercase, uppercase, digits, and symbols scores about 78.7 bits, which rates Strong. Add one more character of any type and the same password reaches about 85.2 bits, which rates Very strong. That is why length is the biggest lever.

How to use Password Strength Checker

  1. Type a password into the box.
  2. Read the strength meter and rating.
  3. Follow the improvement tips to make it stronger.
  4. Add length first if the score is low, then re-check, since length moves the score more than swapping one character for a symbol.

Why use this tool?

  • Entropy-based score, not just a guess
  • Concrete, actionable improvement tips

Tips for best results

  • Test the password you actually plan to use, nothing is transmitted, so it's safe.
  • If the score is low, add length first. It's the biggest lever you have.
  • Watch for common patterns: names, years, keyboard walks, and simple substitutions.
  • Re-check after adding characters, the meter updates live as you type.
  • A top score doesn't protect a reused password, use a unique password per account.
  • When a password scores poorly, generate a fresh one with the password generator instead of patching it.

Frequently asked questions

Is it safe to type my real password here?
Yes. The check runs 100% in your browser, nothing is sent, stored, or logged, so your password never leaves your device.
What is entropy?
Entropy measures how many guesses an attacker would need on average, based on length and character variety. Higher entropy means a harder-to-guess password.
What makes a password strong?
Length matters most, followed by a mix of character types and avoiding common words, names, or predictable patterns.
Does a strong score mean my password cannot be cracked?
No score can promise that. Reuse and phishing are bigger real-world risks, use a password manager with unique passwords for every account.
What does the bits score mean?
Bits measure guessing effort. The tool rates under 28 bits as Very weak, under 36 as Weak, under 60 as Fair, under 80 as Strong, and 80 or more as Very strong. A higher bits score means an attacker needs far more guesses on average.
Why do two passwords of the same length score differently?
Because the score multiplies length by the size of the character pool. A password using lowercase, uppercase, digits, and symbols draws from a pool of 94 characters, while a lowercase-only password draws from 26, so the same length earns far fewer bits.

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