AbstractAnchor impellers are commonly used for the homogenization of non‐Newtonian fluids, often in association with a set of coaxial turbines. The optimal design of such mixers relies on the knowledge of power drawn by the individual impellers. In non‐Newtonian mixing, this can be readily obtained using the Metzner‐Otto (1957) concept. In this article, the Metzner‐Otto concept and the determination of the constant Ks for anchor impellers have been revisited using numerical and experimental techniques for the case of shear‐thinning and shear‐thickening fluids. Contrary to literature findings, it is shown that the constant Ks does not vary strongly with the power law index and that, for mixer design purposes, the use of a constant value of Ks for each of the rheological behaviors considered is adequate.