Inhomogeneous partitioning of fluorescent probes between membrane heterogeneities, or domains, can lead to significant changes in the efficiency of energy transfer between probes. In this paper we develop a quantitative model to relate time-resolved Forster resonance energy transfer (FRET) data to the size of membrane domains. We expand upon a classic approach to the "infinite phase separation limit" and formulate a model to account for the presence of monodisperse disks of finite dimensions within a two dimensional infinite planar bilayer. The model was applied to a simulated model membrane composed of dimyristolphosphatidylcholine (DMPC)/cholesterol within the liquid disordered (l_d) and liquid ordered (l_o) coexistence regime. Two fluorophores, one preferentially partitioning into each phase, were added to simulate time-resolved FRET data. Domain sizes ranging from 5-50 nm were simulated, showing clear differences in the efficiency of energy transfer as a function of domain size within this range. Time resolved data were were fit with both a single parameter (domain diameter only) and a full five parameter fit. Each fitting procedure yielded similar results for the domain diameter; however, analysis of the multi-parameter fit provided a more complete picture as to the experimental applicability of such a technique. We show, using off-lattice simulations and a quantitative analysis, that the method can identify the presence of domains with a diameter of 5-50 nm, with approximately 20% error over a wide range of liquid-ordered fractional coverages.