We use density functional theory to investigate Pt growth on SrTiO3(100) surfaces. We have determined the favored monolayer arrangement for Pt on both terminations of SrTiO3(100). The work of separation as a function of the number of monolayers of Pt has been determined for Pt films of up to 5 monolayers. To examine which surface growth mode will dominate Pt film growth on this substrate, we have also examined isolated Pt clusters on each termination of SrTiO3(100). Our results indicate that the TiO2-terminated surface is more favorable for epitaxial growth of (100) oriented Pt films than the SrO-terminated surface.