Deployed as an add-in for Microsoft Excel, ThreeDify XLCurvFit (XLCurvFit) makes fitting curve equations to any 2D data as easy as highlighting a range of cells within Excel worksheet. XLCurvFit’s built-in library includes a wide range of linear and non-linear curve equations. There are over 5300 out-of-the-box models that are classified into 19 equation families with support for combined equations (i.e., polyfunctions). With a few mouse clicks, XLCurvFit gives engineers and researchers the power to automatically fit thousands of equations within Microsoft Excel, extract the ideal model from their experimental data, and graphically review the fitting results. XLCurvFit saves engineers and researchers precious time by taking the endless trial and error out of curve fitting.