Sure there is, here's an example. This formula is based on my own experience and it works for me:
Here's the way I figure: An Example
1. Using a Harvester with max extraction rate of 4KG/H.
2. Set up in an area of 73% ( any resource ) concentration.
Now, 73% of the max rate of 4KG/H is 2.92KG/H (which is the actual extraction rate).
3. Now, take the actual extraction rate of 2.92KG/H and multiply by 60 ( 60=extracted units per hour per KG ), and you get 175.2 units harvested per hour.
4. So in a 24hour period, the hopper will have (175.2X24) 4205 (rounded)units of the resource you've selected to harvest.
Hmmm,
need a cup of coffee.