excel's curve-smoothing algorithm

[zhytomir]

I have some raw data in excel, with a smooth curve added. I am trying
to reproduce this curve on the same data in GraphPad Prism, with poor
results. Does anyone know how excel calculates curve smoothing?

 

[Bernard Liengme]

As far as I can recall Microsoft uses a cubic spline but I have not seen the
exact formula.
Try Google with search term: excel spline
best wishes

 

[Jon Peltier]

Brian Murphy has determined that the smoothing algorithm is a Bezier curve.
Find the link to this workbook (Smooth_curve_bezier_example_file.xls) in the
bottom part of this page:

http://www.xlrotor.com/resources/files.shtml

- Jon