This advanced spiral groove face seal program was developed to accurately predict the performance of hydrodynamic spiral grooves and other groove shapes (oblique groove and radial groove) for face seals in gas applications such as air or other gases. The governing equation is the compressible Reynolds equation with rarefied gas dynamic effect, so that a high degree of accuracy can be obtained for low-pressure applications in the aerospace industry. Two types of slip flow correction methods are presented. Pressures are specified at both ID and OD of the seal. The groove depth can be a function of radial and circumferential coordinates, although a constant depth is commonly used. Both the inward and outward pumping geometries are included. The analysis option includes a single run analysis and multiple run. Multiple run allows for the design iteration and multiple cases comparison for optimization purposes. Various postprocessor graphics allows for easy presentation and result comparison.