Hey Paul, isn’t that along the line that we discussed yesterday?
Bakemeadowlane - I do the same as Matthew, except that I leave out the PI as it’s the same above and below the line. So to convert, I quickly do the following:
<baking form diameter> x <baking form diameter> / <recipe diameter> / <recipe diameter> I then save that number and multiply all the ingredients with it. I made a 4 layer wedding cake using this math and it came out as expected…. (Trrrrrust me, I’m an engineer!!!!)
If you want to split hairs: For a pie you need to fudge the multiplication factor for the dough a little, as you’ll need about half the dough for the wall (correct me if I’m wrong guys….). So if your baking form is larger than what the recipe calls for I’d go a bit lower on the number, and if you’re using a smaller form go a little higher, i.e. if you’re using 6” instead of 9” my formula would give you 0.444, where I’d probably up the dough to 0.5 or 0.55 to be on the safe side. I wouldn’t worry too much about the 9.5” pan, I’d just use 1.1 time the ingredients.
Btw, Google has a handy calculator built in, just enter 6*6/9/9 in the search line and it spits out the result.