Spreading amounts using Normal Distribution


I want to add a feature to my model that will include these inputs:

Start Date

Number of Months



Then I want the model to spread the amount across the months using a normal distribution (bell curve).  In Excel, I have used the NORMDIST function to calculate the probability be period and then multiply that against the full amount.  


Any ideas?  TIA


  • Hey - it looks like this is currently under investigation in the idea exchange.  Here is a link to the related post:






  • Wouldn't using a standard deviation multiplied by the value based on the % that is associated with the value of the standard deviation, solve the problem?

    Since you are using time, you would just reference a count of months from where you are from the start date to the date you are at.

    IF Start() < Number of Months + StartDate AND START() > StartDate THEN gotta play with this part but Start Month() + CountFromStartMonth/Number of Months * Value/2 * Sd% value (reference a table that gives 100 points on the bell curve and you can do an equation that slides between the two points based on the values that are given if you so desire)

    As for getting the real SD% I would have to go revisit some stats and math to give you a good way to create it.
  • Yeah, I've thought about that. It will be tricky with the different start date and number of months, but I think I can make it work. Was hoping that there was already a stat formula to accommodate that. thanks for the response!