The metal‐silicon interface resistance is an important factor in the total resistance value of a diffused resistor. A contact correction term has to be considered for the design of resistors on an integrated circuit chip. This correction term is explored both experimentally and theoretically. Experimental results of contact correction are obtained for aluminum, sputtered molybdenum, and pyrolytic molybdenum to silicon contacts of various dimensions. Theoretically, a modified transmission line (MTL) model is introduced to describe the contacts of the diffused resistors. This model is based on the considerations of the geometry and the fabrication processes of the diffused resistor and its contacts. Model calculations compare very well with experimental findings. Thus, the equations derived from the MTL model can be used as design formulas to estimate a realistic value of the contact correction term for any given contact size and fabrication process, provided the process parameters are determined experimentally. In addition, the lower limit of the contact correction term is also obtained based on geometrical considerations only.