IF Function with 3 conditions

[ConfusedAtWork]

If a cell says"Y" I want the next cell to have a numerical value, if it says "N" I want it to say "Nil" If it is blank then I want it to stay blank. The first two bits I can do, I just can't do the last.

 

[Gerald Higgins]

This being a matter of preference not fact.

I'm pretty sure it's actually a matter of fact, that the sum() functions are completely unnecessary, as C with no eyes said.
As EXCEL_IN_EXCEL said, both will work, but leaving the SUM() part out gives you a shorter formula which is slightly quicker to input.

Even though it wasn't asked for, thank you for sharing your opinion nevertheless.

Yes, that's one of the features of this board.
Proposed solutions are quite likely to be commented on by other users.
If there are people considering posting, who don't wish to have other people commenting on their posts, they might want to think about that before posting.

 

[JackDanIce]

@ConfusedAtWork combined formula to use a single column (F):

=IFERROR(D11-(IF(E11="Y",$E$1*D11,IF(E11="N","Nil",""))),"")

 

[JackDanIce]

.. and reduced to:

=IF(E11="Y",D11*(1-$E$7),IF(E11="N","Nil",""))

In above, had $E$1 instead of $E$7

 

[C with no eyes]

This being a matter of preference not fact. Even though it wasn't asked for, thank you for sharing your opinion nevertheless. To the poster it is entirely up to you the end user on your preference. Both formulas will work.

That is correct. They will both work. I didn't say you were wrong. I just said they were unnecessary, which is a fact not an opinion.

From the way you wrote your formula, I was under the impression you were not aware of the succinct method. I have worked with many colleagues who were also not none the wiser that sum() is not needed for many of their calculations and assumed you were also unaware.