Abstract In this paper, we present a machining time estimation algorithm for five-axis high-speed machining. Estimation of machining time plays an important role in process planning and production scheduling of a shop. In contrast to the rapid evolution of machine tools and controllers, machining time calculation is still based on simple algorithms of tool path length divided by input feedrates of NC data, with some additional factors from experience. We propose an algorithm based on five-axis machine behavior in order to predict machining time more exactly. For this purpose, we first investigated the operational characteristics of five-axis machines. Then, we defined some dominant factors, including feed angle that is an independent variable for machining speed. With these factors, we have developed a machining time calculation algorithm that has a good accuracy not only in three-axis machining, but also in five-axis high-speed machining.