Among the widely used methods such as transfer length or Cox and Strack methods to determine the contact resistivity of various interfaces, contact resistivity can also be extracted using fully metallized test structures. In this structure, both sides of a sample are covered with metal without any patterning, and the resistance is measured between the top and bottom sides. The contact resistivity with such samples is calculated by subtracting the resistance of the bulk, conductive (if present), and metal layers from the total resistance of the structure. However, it is possible that the contribution of contact resistivity to the total resistance may be overestimated due to the metal’s finite sheet resistance and partial contacting scheme of the sample. These effects result in current traveling through a limited area inside the sample, increasing the contribution of the contact resistivity. In this work, we use a recently proposed spreading resistance model to accurately determine contact resistivity of the fully metallized test structures. We demonstrate a relative error between the proposed formulation and finite element method simulations below 1.3 %. Moreover, we demonstrate the applicability of the formulation experimentally with Ag/MoOx/(p)c-Si/MoOx/Ag structures.