The problem with forecast is that it does a linear regression of the line
through the points so that the line may not actually cross any of the points.
What many of us would like is a function that draws a straight line between
each individual point and extrapolates the value based on each line segment.

"Gary''s Student" wrote:

The FORECAST() function does a great job of linear interpolation as well as
forecasting.
--
Gary''s Student - gsnu200806


"Steve" wrote:

Has anyone written an interpolation function for Excel? I have an equation
that works, but it is a pain to edit and check each time. There should be a
way to standardize it for use with most tables.