CurvFit (tm) is a curve fitting program for Windows. Lorentzian, Sine, Exponential and Power series are available models to match your data. A Lorentzian series is highly recommended for real data especially for multiple peaked and/or valleys data. CurvFit is another improved productivity example do to using Calculus (level) programming ... ie. minutes to solve, days or years to understand solution and what it implies (e.g. wrong model, sampling rate error, etc.). Helps learn 1) whether math model is good for given data; 2) convergence implies a reasonable solution; 3) how to select new starting initial parameter values. See comments in EX*.? files for ideas on how to converge via solvers. Interpolation, extrapolation, & Hardcopy Plot options are now available. Industry problems with solutions over the past twenty plus years have been put into a textbook to show the power of Calculus (level) Problem-Solving. The textbook is on our website at goal-driven.net/textbooks/. The software architect behind Calculus Compilers was Joe Thames. Help future science & engineers get jobs upon graduation. With usage of FortranCalculus compiler, one increases their productivity by a factor of twenty!