Password Entropy Calculator

Security Tools

See how many bits of entropy a password has

FreePrivateInstant
Add a file · .txt .md .csv .json … · up to 2.00 MB
Full guide, 3 min readPassword entropy: what “bits” really mean, and why length beats symbolsRead the story behind this tool →
Embed this tool on your websiteFree
  1. Choose how tall the frame should be.
  2. Press Copy code.
  3. Paste it into your page, blog, WordPress or Notion HTML block.
Height
Live previewAll embeddable tools

The tool runs inside your visitor's browser, nothing is uploaded, and a small "Powered by ToolCloak" line stays under it. The second line (script) is optional: it makes the frame fit the tool's height.

Similar tools you may like

Age CalculatorExact age in years, months, days & next birthday
AI Context Window CalculatorWill my text fit in the model’s context window?
Arc Length & Sector Area CalculatorArc length, sector area and chord from radius and angle
Calories Burned CalculatorCalories burned for any activity
Credit Card Payoff Calculator (Interest & Months)How long to clear your card and the interest you will pay
Daily Protein Intake CalculatorHow many grams of protein you need each day

History

All history →

Password Entropy Calculator — at a glance

Measure the strength of a password in bits.

You paste
Tr0ub4dor&3
Calculate Entropy
Result
Offline attack (10 billion guesses/seco…
Online attack (100 guesses/second): mor…

How to use it — step by step

The password to check. It never leaves your device.

1

Add your text

Paste or type your input into the box. The Sample button fills in an example.

2

Press Calculate Entropy

The result is made instantly inside your browser.

3

Copy the result

Use the Copy button, or send it to another tool.

Pro tips

Small things that make the result better.

✦Length matters more than symbols.
✦Real passwords made of common words are weaker than the number suggests.
✦Do not test a password you still use online.

Quick facts

Freeno signup
Privateruns in your browser
Instantresult in a second
No limituse it as often as you like

Frequently Asked Questions

What is entropy?+

It counts how many guesses a random password of that length and character set would need. Each extra bit doubles the work.

Is the number exact?+

No. It assumes every character is picked at random. A password like Password1! scores high but is easy to guess.

Is my data safe?+

Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.

Is this tool really free?+

Yes — completely free, no signup, no watermark and no usage limit.

More Free Tools

Guides you might like

All guides →
Password GeneratorYour password is not weak because it is short. It is weak because it is yours.
Caesar Cipher & ROT13Caesar cipher: why only 25 keys means anyone can crack it
TOTP Code GeneratorHow the 6-digit code in your authenticator app works (TOTP explained)
IBAN ValidatorIBAN explained: how the mod-97 check catches typos and what each part means