Drop down value to change sum of another box

Hello.

I am trying to create a simple function for my drop down list.
Right now you can select "Yes" or "No" in the drop down list.

I would like that when you select Yes the sum of a field changes (H18).

The background of this is that i am setting up an sheet to calculate monthly interest from different loans i have.

This drop down list should represent if i want to make monthly payments on the actual loan itself or only pay the interest.

Column called: Interest free
Value: YES (Equals no interest)
Value: NO (Pay interest)

Field H18 is the sum of H4 to H12 which are the interests from the loans.
Field H18 is also the sum of i4 to i12 which are the payments on the loans.

I would like that when i Select Yes (no payment on the loan) the H18 is substracted with the sum in the correct "i" field.

I hope that i explained this in the correct way,

I can try and upload the sheet so you can have a look at it.

Thanks for the help.

To clarify things a little it might help to outline the expected values given your sample data.

So for ex. given sample the value in H18 should be ?

If E5 changes from Yes to No the value in H18 should become ?

I would add that for H15, H18 you can look to shorten the existing syntax by using the SUM function

H15:
=SUM(H4:H12)

H18:
=SUM(H15,I4:I12)

pending your locale (Denmark perhaps ?) you will need to adapt the above slightly

On the subject of Location: if the locale defined in your profile is incorrect (which I suspect it is) you should update it

As I suspect you know your locale can have a significant bearing on the correct syntax, people will generally try to adapt their suggestions based on your locale... if your locale is wrong then there's a good chance you won't be able to copy & paste the suggestions into your own file without error.

Perhaps then:

H18:
=SUM(H15,SUMIF(E4:E12,"No",I4:I12))

If necessary (per regional setting config.) change , in above formula to ;