I have a getup I am making that has 15 planets split between reactive metals and toxic metals to make construction blocks. To fully bring these to construction blocks do I need 2 factory planets or 3? Most of the planet are rich and I want to check to move extractors every 4 days. In the same system there are only barren and temperate so that limits me to 2 factories

What’s the total output of your extraction planets per hour?

How much input can a single factory handle per hour?

(Knowing 1 and 2) How many factories do you need?

How many factories fit on your factory planet?

(Knowing 3 and 4) How many factory planets do you then need?
You can do the math! I could guess ‘two’ factory planets, but I can be wrong.
Hello !
IIRC extractor planet for P2 can feed 2 P2F
If look say at integrity response drone, http://www.hstsoft.de/korai/Eve_PI_Diagrams_v1_4.pdf
A P4F requires 6 of each P3 per hour, so needs 2 P3F of each (total 6 P3F) . Each of them needs 2 P2F to be fed, for each of the three mats.
So a P4F needs 4 of each of the 9 P2F to be fed. Considering a planet is 2 P2F, a single P4F needs 18 P2 planets to be fed.
On the other hand, a nanofactory only needs 4 types of P2 so 8 P2 planets (plus P1, can be extracted on factory)
Of course if you have short cycles the output of P2F can be higher.