Is your prediction based on linear progress (i.e., if you're halfway
done, it will take twice the total elapsed time)? or some other function?

A linear solution:

A1: <start date
A2: <% completed
A3: =A1 + (TODAY()-A1)/A2

In article ,
Frontier wrote:

I need to be able to predict a date of completion through a percent completed
over a year, please, please help!!!