Extract from a table a value by interpolating

[Maria]

Hi,

I'm a new with fancy things in excell and would very much appreciate the help.

I have a table from which I want to extract values, but I want those values
to be interpolated from what is in the table. How can I do that?

Thanks,

Maria

 

[Raz]

hi, this is how i do it.
Lets say your table is at A12 to B20
make another column at column C with this equaition =(B14-B13)/(A14-A13)


A B C
12 2.000 1.000 0.5
13 4.000 2.000 1.0
14 6.000 4.000 1.0
15 8.000 6.000 1.0
16 10.000 8.000 1.0
17 12.000 10.000 1.0
18 14.000 12.000 1.0
19 16.000 14.000 1.0
20 18.000 16.000 1.0

Your original value which you need to interpolate from the table, put it in F8
in F9 (or where you want your interpolated value to shop up) put this
equation below.

=VLOOKUP(F8,$A$12:$D$20,2)+VLOOKUP(F8,$A$12:$D$20,3)*(F8-VLOOKUP(F8,$A$12:$D$20,1))

this should work. works for me,
let me know any prob.

Raz