Password Entropy & Strength Calculator
Calculate password cryptographic Shannon entropy bits, pool character size, and brute-force crack time.
- 100% free
- Private in browser
- No signup
- No watermarks
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About Password Entropy & Strength Calculator
Calculate password cryptographic Shannon entropy bits, pool character size, and brute-force crack time. Enter Password Length, Includes Lowercase and Includes Uppercase and the tool works out Entropy, Character Pool Size and Brute Force Time straight away. Everything runs in your browser, so your data never leaves your device.
How to use Password Entropy & Strength Calculator
- Enter Password Length, Includes Lowercase and Includes Uppercase.
- Adjust the remaining options (Includes Digits and Includes Special Symbols) to match your case.
- Read Entropy, Character Pool Size and Brute Force Time in the results panel — copy or download what you need.
Key features
- Shows Entropy (Bits)
- Shows Character Pool Size
- Shows Brute Force Time (Log10 Seconds at 10B/sec)
- 5 adjustable inputs, results update as you type
- No signup, no limits
Frequently asked questions
- Is this calculation free and private?
- Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.
- What does the Password Entropy & Strength Calculator give me?
- It works out Entropy, Character Pool Size and Brute Force Time, updating live as you change the inputs.
- What do I need to enter?
- Just Password Length, Includes Lowercase, Includes Uppercase, Includes Digits and Includes Special Symbols. Every field has a sensible default you can start from.
- Is my data uploaded anywhere?
- No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.
- Does it work on a phone?
- Yes. The layout adapts to small screens and needs no app or signup.
Related In-Depth Guides
Learn practical workflows, real-world examples, and expert tips in our comprehensive guides:
Password Entropy Explained: How Bits Measure Brute-Force Cracking Time
Understand Shannon entropy in passwords, character pool combinations, and how many seconds, years, or millennia it takes GPUs to crack modern passphrases.
Password Strength, Entropy, and QR Codes: Everyday Security Basics
Generate strong passwords, measure entropy, and create QR codes for Wi-Fi or links — practical security hygiene with free browser tools.