Password Entropy Calculator
Calculate password entropy in bits to evaluate brute-force vulnerability.
Password Entropy Calculator
🟢 Excellent: Very strong against brute-force attacks.
About Password Entropy Calculator
The Password Entropy & Crack Time Calculator measures the mathematical strength of passwords in bits ($E = L \times \log_2(R)$), estimating brute-force cracking times across consumer GPUs, cloud cracking rigs, and supercomputers.
How to Use Password Entropy Calculator
Step 1
Type or paste a password into the input field.
Step 2
Review the calculated entropy bits badge and character pool breakdown.
Step 3
Inspect the estimated time to crack across different attack scenarios.
Step 4
Follow recommendations to increase entropy if score is under 60 bits.
Practical Use Cases for Password Entropy Calculator
Password Security & Compliance Auditing
Analyze password strength objectively using mathematical entropy rather than arbitrary length-only rules.
Brute-Force Attack Resistance Benchmarking
Calculate how many hours, years, or centuries a password would resist against a 100-GPU offline hashcat cracking cluster.
Input & Output Examples
Calculating Entropy for 16-Character Mixed Password
Password: "k9#Vp2$mZ8@qL1!w" (Length: 16, Pool: 95 ASCII characters)
Entropy: 105.1 bits | Crack Time (100B guesses/sec): 6.8 Trillion Centuries | Rating: VERY STRONG
Key Features & Performance
- ✓Calculates exact Shannon entropy in bits based on character pool size and password length.
- ✓Estimates crack times for Online Throttled (10 guesses/sec), Fast Hash (10B/sec), and GPU Rig (100B/sec) scenarios.
- ✓Detects common dictionary patterns, sequences (`12345`), and keyboard walks (`qwerty`).
- ✓100% Client-Side memory execution guarantees password privacy.
- ✓1-Click Copy strength report.
Key Terminology & Definitions
Password Entropy (Bits)
A mathematical measure of password unpredictability ($E = L \log_2 R$, where $L$ is length and $R$ is character pool size).
Character Pool Size ($R$)
The total number of possible unique characters available (e.g. Lowercase=26, Alphanumeric=62, Full ASCII=95).