Abstract-The employment of a large number of structurally identical cores on a single silicon die is generally regarded as a promising solution for tera-scale computation, known as manycore chips. To ensure the product quality of such complex integrated circuits before shipping them to final users, extensive manufacturing tests are necessary and the associated test cost can account for a large share of the total production cost. By introducing spare cores on-chip, the burn-in test time can be shortened and the defect coverage requirements for core tests can be also relaxed, without sacrificing quality of the shipped products. If the above test cost reduction exceeds the manufacturing cost of the extra cores, the total production cost of manycore chips can be reduced. In this paper, we develop novel analytical models to study the above tradeoff and we verify the effectiveness of the proposed test economics model for hypothetical manycore chips with various configurations.Index Terms-Analytical model, manycore chip, product quality test economics.