CurvFit v6 is a curve fitting application for Windows that allows users to match data with Lorentzian, sine, exponential, and power series models. It is recommended for analyzing multiple peaked and/or valleyed real data using a Lorentzian series. The application helps users determine whether a mathematical model is suitable for given data and how to select initial parameter values to achieve convergence of solutions. Additional features include interpolation, extrapolation, and plotting options. The software was created using a calculus-level compiler to greatly increase productivity for solving problems.