The grinding power is often used as a parameter for monitoring the grinding process. The power may also be used to monitor the effects of dressing. Empirical models are required to guide the selection of the dressing and grinding conditions. In this paper, the effects of dressing conditions and grinding conditions on grinding force and grinding power are reviewed. The effects of grinding conditions and dressing conditions on grinding force and grinding power are related to the shape of the idealized chip thickness. It is found that the grinding force and grinding power can be related to the dressing operation by considering the effective density of the cutting edges on the wheel surface. The semi-empirical model developed in this paper can be used to predict the variation of the grinding power during the wheel redress life cycle. Therefore the model can be used to guide the selection of dressing and grinding conditions. The potential use of the model for adaptive control of the grinding process is also described.