A while ago, somebody had posted a guide about how to use the Google spreadsheet to pull the data from official grand exchange website and use them for some calculation. Therefor, I have make the a herblor calculator that similiar with the one on wikia.
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1. Why i make another calculator there already exist one on the wikia?
because how wikia evaluate the cost of making potion is not right.
First, it use the price of potion (3) instead of potion (4) in it's calculation. Since the Bob Barter at the Grand Exchange can decant the potion in the noted form, I believe most potion are traded in the form of 4 doze per vial, so using the price of potion (4) is more accurate.
Second, it assume the value of untradeable stuff to be zero, which is terribly wrong. For some example, Nightshade is an untradeable ingredient that are using in weapon poison++, and collecting Nightshade is time costing. So in my calculator, I assume it value is 8000 gp.
2. Why I didn't include the torstol?
Because for the item that has value more than 10k, the website will not provide an accurate price, which will make the evaluation about cleaning torstol not that useful.
Instruction
The first page of the spreadsheet is the cost evaluation about potion making, and the second page is profit about herb cleaning. With some basic calculation about the gp/xp, I also place the result of xp/hr and gp/hr, so you can have more information about whether potion mkaing or herb cleaning is more suitable for you.
The third page is the price of all the ingredient. If you are interested about the value I set for untradable stuff, see the bottom of this page.