VLECalc is a vapor liquid equilibrium calculator designed especially for chemists and engineers that develop or operate chemical manufacturing processes which use organic solvents. The program lets you perform bubble-point calculations using pure component vapor pressure parameters (Antoine constants), and design an activity coefficient model (ideal, UNIFAC, or NRTL). In addition, you can simulate a simple batch distillation and solvent replacement operation, estimate the vapor pressure and boiling point of an organic mixture, and save your data.