Entropy Meter
Measure Shannon entropy of any string. See character distribution and how long it would take an attacker to crack it.
Input
stays in your browser
Max 5 MB · text files only
Length
0
characters
Unique chars
0
— alphabet
Shannon entropy
0.00
bits / char
Total entropy
0.0
bits
0406080128+ bits
Type something to begin.
Two ways to measure:
Shannon entropy measures actual unpredictability of the string you typed (low for "aaaaaa", high for random).
Charset-based entropy assumes the attacker knows your alphabet and brute-forces it — more relevant for passwords.
Shannon entropy measures actual unpredictability of the string you typed (low for "aaaaaa", high for random).
Charset-based entropy assumes the attacker knows your alphabet and brute-forces it — more relevant for passwords.
Character distribution
Time to crack (offline brute-force)
| Attacker | Speed | Avg time |
|---|
Estimates assume the attacker brute-forces the full charset of your input (worst case for them, best for you). For known weak passwords (like "password123"), real attackers use dictionary attacks that are much faster than these numbers suggest. Speeds reflect 2024-2026 GPU benchmarks against various hash algorithms.