Martensitic stainless steels have high hardenability, good strength and good corrosion resistance; however, high power consumption is encountered in machining operations due to their hard machinability. The consumption should be eliminated for cleaner production in terms of sustainable machining. Therefore, this study aims modelling of cutting forces and power consumption in turning of AISI 420 martensitic stainless steel based on finite element method. Finite element modelling of cutting forces is preferred to estimate optimum cutting parameters for less power consumption. In this regard, finite element simulations are performed based on three different levels as cutting speed, depth of cut and feed rate. Depth of cut could be assessed as the most important factor with percentage contribution ratio of 49.55% in respect of the power consumption. The average of 7% difference is achieved between experimental and simulated cutting forces. The deviation of 4.5% is evaluated between experimental results and simulation outputs by means of comparing the power consumption. The finite element modelling of cutting forces and power consumption is quite compatible with the experimental results, and it can be performed by high accuracy without excessive machining experiments of difficult-to-cut materials.