{Sum(if(...))*Sum(if(...))} Macro Help

[DBWright]

Currently I have 3 sheets:
Sheet 1:
........Jan Feb Mar
CustC 21 33 0
CustB 1 4 7

Sheet 2:
........Jan Feb Mar
CustB 6 7 0
CustC 9 6 8

Sheet 3:
........Jan Feb Mar
CustB
CustC

For Sheet 3, I need it to find CustB for the corresponding months in Sheets 1 and 2 and find the product. My current formula for CustB for Jan is:

{Sum(if(B2&A2=Sheet1!B2:C2&Sheet1!A1:A3,B2:C3))*Sum(if(B2&A2=Sheet2!B2:C2&Sheet2!A1:A3,B2:C3))}

The problem is, my dates go from Jan-11 to Dec-16 and I have 260 customers. I don't need to find just CustB, the formulas are populated for every customer on sheet 3. Therefore, when I populate formulas in all cells in sheet 3, it takes forever to run. When I change something in Sheets 1 or 2, it re-calculates and takes forever as well.

Is there a way to macro such a function?

 

[psrs0810]

try recording the macro first. Then post it and someone may be able to help you with the specifics