MATLAB GUI Sumulations is a graphical user interface (GUI) used to model the optical properties of single metal nanoparticles and uses a modification of the quasi-static approximation, a widely used method for simulating single small-particle scattering.  MATLAB’s guide utility was used to program the GUI.  Optical constants data for Au, Ag, and Cu are included with the GUI and can be easily replaced with data for other materials.  The dielectric constants for vacuum, air, water, and oil are provided, but a user-specified value can also be entered. The options for plotting include the electric polarizability, dielectric function, and the absorption/scattering/extinction cross-section/efficiency.  There is an option to compare computed results for spherical particles with those computed using Mie theory.  All plots can plotted against incident wavelength (nm) or photon energy (eV).  Please view the readme file for installation.