Tools / Drake equation calculator
Interactive tool
Drake Equation Calculator
Explore how uncertain assumptions change a model average. These are teaching examples, not measured counts.
Try your own assumptions
Every starting value below is an illustrative choice, not a scientific best estimate. Change one input at a time and watch what happens.
Rate per year; illustrative input.
0 to 1. For example, 0.5 means half.
Average count, not a fraction; can exceed 1.
Unknown: explore an assumption from 0 to 1.
Unknown: explore an assumption from 0 to 1.
Unknown: explore an assumption from 0 to 1.
Duration of detectable signs; not necessarily total lifespan.
Model average of detectable civilisations in the Milky Way
What does this number mean?
N is a model average of civilisations in the Milky Way producing detectable electromagnetic signs. It is not a probability, a known count or a prediction of signals we will receive.
Calculation: N = R* × fp × ne × fl × fi × fc × L. Rates use years; the fraction inputs range from 0 to 1. The starting example returns 10.
The classic simplified model assumes a steady rate. Input ceilings are interface limits, not scientific bounds.
Read the full Drake equation explanation →