Finding the most cost-effective configuration of a two-stage gearbox's primary design characteristics, including the second stage's double gear sets, is the goal of this article. The optimisation process takes ten parameters into account, including the total gearbox ratio, the width coefficient of the first gear stage, the width coefficient of the second gear stage, the allowable contact stress of stage 1, the allowable contact stress of stage 2, the output torque, the cost of the gearbox housing, the cost of helical gears, the cost of straight gears, and the cost of shafts. Furthermore, in order to discover the best answer, a simulation experiment is run. It turns out that the responsiveness is primarily affected by the overall gear ratio. The suggested approach has shown its dependability and is suitable for use in future research