VBA Excel add-in utilities and worksheet templates

Fourth-order, zero phase-shift Butterworth low-pass filter & adaptive butterworth filter (version 3 -22 august 2024).  Download: ,

Polynomial curve fitting, interpolate, extrapolate: XlXtrFunâ„¢ Extra Functions for Microsoft Excel.    (Advanced Systems Design and Development, Red Lion, USA). A shareware alternative that also works on Windows XP x64 is available via the .

Compute standard ellipses, confidence ellipses and prediction interval ellipses.  Download: