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Password Entropy Calculator

Measure password strength using entropy (bits) and estimate time to crack.

Password Entropy Calculator

Understand the true mathematical strength of your password. Calculated purely on information theory, not just dictionary lists.

Entropy Bits
0

Bits of randomness

Character Pool
0
Crack Time
0s

@ 1 Trillion guesses/sec

How it works

Entropy is calculated using the formula E = L × log₂(R), where L is usage length and R is the size of the character pool.

Why Pool Size Matters

Adding a single symbol increases the pool size from 62 to ~95. However, adding length (L) has a much larger exponential effect on total entropy than just adding symbols.

Password Entropy Calculator

Password Entropy Calculator evaluates how secure a password is using information theory instead of guess-based rules.

Last Updated: January 15, 2025

# What is Password Entropy Calculator?

Password entropy measures the unpredictability of a password in bits, representing how resistant it is to brute-force attacks.

# How Does Password Entropy Calculator Work?

  • 1Detects the character sets used.
  • 2Calculates entropy based on length and pool size.
  • 3Estimates brute-force crack time.
  • 4Displays strength visually.

# Common Use Cases

Checking real password security.

Learning why length matters more than symbols.

Security awareness training.

# Why Use This Tool?

Scientifically accurate.
100% client-side.
No password storage.

Trusted & Secure

• Runs fully offline in your browser
• Calculations based on information theory
• No passwords stored or transmitted

# Frequently Asked Questions

Is entropy better than strength meters?▼
Yes. Entropy is mathematically grounded and avoids misleading rule-based scoring.
Is my password sent anywhere?▼
No. All calculations are performed locally in your browser.

Last updated: January 2025 • v2.1.0 • Privacy First • Secure & Encrypted

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