Entropy Calculator

Quantify your security. Calculate the mathematical entropy of your password to see how many "guesses" it would take for a computer to crack it.

Test a Password We do not store or send your password anywhere.

Information Entropy

0 Bits

Time to Crack (Offline)

Instant

What is Password Entropy?

I genuinely believe that "complexity" is a trap. Many sites force you to use a capital letter and a symbol, which just leads everyone to use `P@ssword1`. Entropy is a measure of how unpredictable a password is. A long string of random lowercase words (e.g., `correct horse battery staple`) often has much higher entropy than a short, "complex" password.

The Math: Entropy is calculated as `log2(R^L)`, where `R` is the size of the character pool (lowercase, uppercase, numbers, symbols) and `L` is the length of the password. Every additional bit of entropy doubles the time it takes to crack the password.

Security Benchmarks:

Under 40 Bits: Very Weak. Can be cracked in seconds or minutes by a modern GPU.
60-80 Bits: Strong. Safe for most personal accounts against common attacks.
100+ Bits: Exceptional. Extremely difficult to crack even with massive computing power.
Passphrases: Use 4 or 5 random words. They are easy for you to remember but hard for computers to guess.