Entropy Calculator
Analyze password cryptographic security using Shannon Information Entropy mathematics. 100% local calculation.
Brute-Force Attack Benchmarks (Est.)
| Attack Scenario | Speed Rate | Estimated Time to Crack |
|---|---|---|
| Standard Web App (throttled) | 100 guesses/sec | — |
| Desktop CPU (offline script) | 100,000 guesses/sec | — |
| GPU Brute Force (High-end) | 10,000,000 guesses/sec | — |
| GPU Cluster (Supercomputer) | 100,000,000,000 guesses/sec | — |
How entropy is calculated
Information entropy represents the complexity or unpredictability of a password. It is calculated using the formula:
Entropy (E) = L × log₂ (R)
Where L is the password character length, and R is the pool size of unique characters available. If a password contains only digits (0-9), R = 10. If it contains both digits and lowercase letters, R = 36. An entropy level above 60 bits is generally considered secure against standard offline attacks, while 80 bits or higher is highly resistant.
What is the Password Entropy Calculator?
The Password Entropy Calculator calculates the mathematical entropy (randomness) of a password in bits. It estimates the time it would take to crack the password under various brute-force attack scenarios.
How it Works
It determines the character pool size (R) and length (L) to calculate entropy: $E = L \times \log_2(R)$. It then calculates brute-force timelines based on hypothetical guessing rates.
Benefits of local generation
- Calculates cryptographic entropy.
- Estimates cracking timelines.
- Fully offline calculations.
Security Information
All calculations are performed locally in browser memory. No data is stored or logged.
Best Practices
- Aim for at least 60 bits of entropy for personal accounts.
- Aim for 80+ bits of entropy for master passwords.
- Avoid sequential or repetitive patterns.