This paper describes a novel real-time based optimal Pulse Width Modulation (PWM) method suitable for microprocessor-based PWM inverters. Optimal switching patterns minimizing the performance index corresponding to the distortion between the reference and the controlled output voltages are decided by on-line calculation using the microprocessor-implemented control system. To show the effectiveness of the proposed PWM scheme, digital simulation studies and experiments using a 16-bit single-chip microcontroller (Intel 80C196KC) are performed. The results obtained from these simulation studies and experiments show that the proposed PWM scheme has better performance than the other methods such as the natural PWM and the direct PWM.