This research proposes a general formula for implementing in the control system of a dry-jet wet spinning machine to achieve a specific diameter size for Polysulfone hollow fibers. By employing Taguchi method, the effect of the operation parameters on the fiber geometry is investigated. The findings emphasize the significance of various fabrication parameters in determining the inner diameter (ID) and outer diameter (OD) of the hollow fibers. To mathematically predict the ID and OD, a first-order equation is developed using the least squares method. The accuracy of the proposed equation is validated through a series of experiments, where the ID and OD of the produced hollow fibers are determined using cross-sectional images by a scanning electron microscope. The results demonstrate a strong agreement between the proposed equation and the experimental data, with a maximum error of less than 7%. This research offers a valuable tool for optimizing hollow-fiber spinning plants and holds promise for improving their overall performance.