Data Curve Fit Creator Add-in is an easy-to-use data analysis add-in for Microsoft Excel. It adds curve fitting, interpolation, and data smoothing functions to Excel. Curve fitting functions include polynomial fits and a versatile local regression (loess) function. Interpolations include linear, cubic spline, bessel and monotonic 'constrained' splines, as well as a 'flexible spline' that allows you to specify the slope at each data point. Data smoothing functions include moving average, median filter, and a Gaussian smoothing filter. Data Curve Fit Creator Add-in also includes automatic sorting and data repair functions.