This document describes the development of an artificial neural network (ANN) and graphical user interface (GUI) to estimate fabrication time in rig construction projects. The ANN was trained on data from 960 completed fabrication jobs. It uses height, plate thickness, and inspection criteria as inputs to predict fabrication time in days as the output. Eleven different ANN architectures were tested and the model with 3 input nodes, 50 hidden nodes, and 1 output node performed best with a mean squared error of 1.35337e-2. A GUI was created allowing users to input job parameters and receive a fabrication time prediction without ANN expertise. The developed ANN and GUI provide a data-driven method for fabrication time estimation in rig construction project