From the Not Just Numbers blog:

Please accept my apologies for the lack of posts these last couple of weeks – I’ve been away on holiday, chilling out on the Isle of Skye (that’s me in the picture relaxing on the coral beach near Claigan).

I had intended to write some posts in advance but it didn’t exactly work out as planned!

Now I’m back, I thought I’d write a (vaguely) holiday related post.

If you want to know how to work out the number of working days between two dates (allowing for weekends AND holidays), read on.

To do this, we can use the NETWORKDAYS function.

The syntax for this function is:

=NETWORKDAYS(StartDate,EndDate,[Holidays])

I would not recommend entering the dates directly into the function. This is not only good advice for making this particular function work, but it is best practice when referring to any variable in Excel – enter its value in a cell and refer to the cell.

Ignoring the optional argument, if A1 contains 1/8/2014 and A2 contains 31/8/2014, then

=NETWORKDAYS(A1,A2)

returns 21, being the number of working days in August 2014 (if you ignore public holidays).

The best way to use the optional third argument is to refer to a range, where you can enter holiday dates. So, say we add the third argument as follows:

=NETWORKDAYS(A1,A2,B1:B20)

We can now enter the dates of any holidays in cells B1 to B20 and these will be excluded from the calculation.

So, in the UK, last Monday was our August Bank Holiday, so if we enter 25/8/2014 into any of the cells from B1 to B20, the formula returns 20.

A practical way of using this functionality would be to enter the whole year’s holidays into the range referred to (B1:B20 in our example), any of those dates that fall between the start and end dates would then be excluded from the calculation.

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