CurTiPot is a powerful all-in-one freeware for acid-base equilibria calculations such as pH of aqueous solutions, dissociation degree of weak and polyprotic systems, pKa determinations, simulation of titration curves and analysis of real titration data with chemometric tools like interpolation, smoothing and regression. The program is free of charge for non-commercial use, be it personal, in classroom (high school and college), laboratory or research and provides: - pH calculations of strong, weak an multiprotic acids, bases, salts and their buffers and mixtures (over 30 species at once) in aqueous medium, with estimation of activity coefficients by the Davies equation; - Analysis of pH vs. volume of titrant data of simulated and real potentiometric titration curves by two methods: i) graphical representation of curves, assisted by cubic splines interpolation and smoothing of derivative curves for accurate evaluation of inflections (end-points); ii) determination of concentrations and refinement of pKa values by multiple nonlinear regression (based on the Solver supplement of Excel), essential for difficult titrations with undefined inflections, for example, acid rain. - Simulation and overlay of acid-base titration curves of any complexity, without or with simulated random experimental error in pH and/or volume. Valuable for teaching, generation of unlimited titration exercises and evaluation of the feasibility and accuracy of new titrations. - Generation of protonation diagrams and distribution curves of the equilibrium species of acids and bases as a function of pH or of added volume of titrant. All necessary spreadsheets with graphics, examples, instructions, database and visual basic macros are contained in the single curtipot_.xls file. Simply unzip it, open it with Microsoft Excel (at medium security level), activate macros and start learning and working. No install/uninstall required, all macros removed when closing file.