# Excel: How do I calculate net workdays for an array of date ranges?

I have a list of date ranges, let's say:

``````        A                   B
1 April 25, 2013     May 31, 2013
2 September 30, 2013 October 18, 2013
``````

I need to calculate a sum of net working days of all ranges into a single cell. I want to avoid intermediate =NETWORKDAYS(). An array formula is a logical choice, but an attempt to apply it, like this `{=SUM(NETWORKDAYS(A1:A2, B1:B2))}` leads to a formula error.

How can it be done?

More broadly, how does Excel apply an array formula? It is not clear to me from basic array formula examples.

## 1 Answer

Try this version

`=SUMPRODUCT(NETWORKDAYS(A1:A2+0, B1:B2+0))`

NETWORKDAYS accepts "arrays" but not ranges (in Excel 2007 or later) so the +0 converts the range to an array

`SUMPRODUCT` instead of `SUM` means you don't need to "array enter" the formula

If you use `SUM` then you "array enter" by doing this:

1) Select cell with formula

2) Press F2 key to select formula

3) Hold down CTRL and SHIFT keys and press ENTER

if done correctly you get { and } around formula

• I like SUMPRODUCT version. – DKroot Jun 19 '13 at 3:10