Tighter tolerances are becoming more prevalent as thermoforming applications are increasingly utilized in multiple component assemblies with load bearing and other functional capabilities. A, analytical method is described for shrinkage predictions utilizing a thermoviscoelastic constitutive model to try and avoid costly and time consuming forming trials by determine adequacy of the mold and process a-priori. Validation experiments and sensitivity analyses were performed to understand the process behavior and estimate the accuracy of the shrinkage analysis. Design and manufacturing guidelines it-ere then developed to facilitate tight tolerance thermoforming. While the analysis was generally capable of predicting linear shrinkage, statistical yield models indicated that improved process control and further process development is required to consistently produce thermoformed parts to tight tolerances.