You could try this:

Assume that your dates are in A2:A7 and your values are in B2:B7. B3:B6 are
blank.

Put the following formula in B3, and then copy it down for B4,B4,B5 and B6.

=$B$2+($B$7-$B$2)*(A3-$A$2)/($A$7-$A$2)

Art
"Taha" wrote:

> Hi,
>
> I have a set of data that has monthly (or sometimes biweekly) measurements.
> However, I need to interpolate the daily values using the actual consecutive
> data. However, I do not want to put a best-fit line or curve through the data
> for the whole year. I want the program to pick between two consecutive
> values, and depending on their relationship (linear increase or decrease),
> fill in the gaps between them and spit out the corresponding values. For
> example, I have the following set,
>
> Date Value
> Jan. 10 0
> Jan. 15 5
>
> what I need is this:
>
> Date Value
> Jan. 10 0
> Jan. 11 1
> Jan. 12 2
> Jan. 13 3
> Jan. 14 4
> Jan. 15 5
>
> However, the next day could be Feb. 2 and the values could be negative and I
> want the program start filling the days between Jan. 15 to Feb. 2 without
> using the Jan. 10 value. I hope I am making myself clear. I dont know if
> there is a program, macro or a function that can do that. I would appreciate
> if you could help me.
>
> Thanks in advance,
>
> Taha
>
>
>