Multiplying percentage from dropbox by a different value in separate cell

Hi, welcome to teh forum

Hard to be exact without seeing a sample of what you are working with, but I have a feeling you are over-complicating this. If you are applying teh same % to all values, then just sum the values and apply the % to the total.

Below are 3 different ways to do this.
The 1st is how I described above
the 2nd uses sumproduct
the 3rd rune the cals on each row and sums that totao - this is just to checvk teh answers

	A	B	C	D	E	F
1	0.1	10	165		11	165
2		20	165		22
3		30			33
4		40			44
5		50			55

1. C1=SUM($B$1:$B$5)*(1+A1)
2. C2=SUMPRODUCT((B1:B5)*(1+A1))
3. E1=B1*(1+$A$1)
copied down
F1=SUM(E1:E5)

So, all you really need to to add the rows and apply the % to the total