The Drake Equation:

Estimate the number of communicative extraterrestrial civilisations in our galaxy

N = R* fp ne fl fi fc L
2471 5
0.5
2.5
0.5
0.5
0.5
3162

N: The number of civilisations in our galaxy with which communication might be possible.

R*: The average rate of star formation in our galaxy.

fp: The fraction of stars which have planets.

ne: The average number of potentially life-supporting planets per star which has planets.

fl: The fraction of potentially life-supporting planets on which life does arise.

fi: The fraction of life-hosting planets on which intelligent life arises.

fc: The fraction of civilisations which exhibit a detectable technosignature.

L: The length of time for which these civilisations exhibit a detectable technosignature.