🧑‍💻 Developer

Password Strength Checker

Check how strong a password is and how long it would take to brute-force. Nothing leaves your browser.

Results

Strength
Strong
Entropy
72 bits
Brute-force time (10B guesses/s)
9,012.1 years
Tips

📊 Password Strength Checker chart

Visual summary of your results.

What is the Password Strength Checker?

Check how strong a password is and how long it would take to brute-force. Nothing leaves your browser. Everyday utilities for developers — encoders, formatters, hashes and generators — that run locally in your browser with standard Web APIs. No data is sent to any server.

Password Strength Checker – free online developer tool illustration
Password Strength Checker — free, exact and private.

How to use the Password Strength Checker

  1. Enter your password.
  2. Results update automatically as you type; you can also press Calculate.
  3. Read the output: strength, entropy, brute-force time (10b guesses/s), tips.
  4. Use the 📊 chart to see the result visually, then copy or share it.

Formula and method

Entropy = length × log₂(character pool); estimate only — real attacks also use dictionaries

Worked example

With password = Tr0ub4dor&3, the Password Strength Checker returns strength: Strong; entropy: 72 bits; brute-force time (10b guesses/s): 9,012.1 years.

Tips for better results

  • Hashes use the Web Crypto API and match command-line tools such as sha256sum.
  • Never paste production secrets into any website — even client-side tools.
  • Use JSON Validator before JSON Formatter to see precise error positions.

Frequently asked questions

What does the Password Strength Checker do?

Check how strong a password is and how long it would take to brute-force. Nothing leaves your browser.

How is it calculated?

The Password Strength Checker uses this method: Entropy = length × log₂(character pool); estimate only — real attacks also use dictionaries.

Can you show an example?

With password = Tr0ub4dor&3, the Password Strength Checker returns strength: Strong; entropy: 72 bits; brute-force time (10b guesses/s): 9,012.1 years.

Is the Password Strength Checker accurate?

Yes. It uses standard formulas and exact constants, and the results are verified by our automated test suite. Values are displayed to up to 12 significant digits.

Is this tool free and private?

Yes — the Password Strength Checker is completely free with no sign-up, and it runs entirely in your browser, so the values you enter are never uploaded to our servers.

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