I have a basic excel spreadsheet like this:

A B C D etc.. 10% 219.10 34.2 6.4 etc.. 6% 45.10 36.2 7.4 etc.. 4% 419.10 54.2 9.4 etc.. Totals: [SUM] [SUM] [SUM] ( -- update - need totals here -- )

I would like to sum all the values in column B, C and D. Each cell value needs to be multiplied by the % in column A before doing the sum()

I could manually create a new column to contain the % calculation, and sum that column up, but I’m hoping to do it without the additional column.

I found this which I think is on the right track but am a little lost at implementing it.

(planning to write this calculation to an excel spreadsheet created from a php script based on values in a simple mysql database)

### EDIT

For the updated question, all you need is (in B5)

```
=SUMPRODUCT(B2:B4 * $A2:$A4)
```

Copy to the right

For E2, use

```
=SUMPRODUCT(B2:D2 * $A2)
```

This means B2*A2 + C2*A2 + D2*A2.

But, **did you know** that mathematically speaking, it is the same as

```
B2*A2 + C2*A2 + D2*A2
= A2 * (B2+C2+D2)
```

Which is just this below?

```
=A2*SUM(B2:D2)
```

Looking at your etc, if you need to expand it rightwards, just keep column A locked in SUMPRODUCT, or use the SUM. Example below for up to J

```
=SUMPRODUCT(B2:J2 * $A2)
=A2*SUM(B2:J2)
```

And copy down.

### Answer：

Use array formulas e.g. http://office.microsoft.com/en-us/excel-help/introducing-array-formulas-in-excel-HA001087290.aspx

These are generally expressed by the control-shift-enter idiom

Tags: excelexcel, function