This research was focused on development of a large square baler mass measurement system. The mass measurement system was designed to provide estimations of mass yield, mass flow, individual flake weights, and bale weights. The developed mass measurement system was evaluated at the same level as the measured ground truth which was defined to be on a bale basis. The mass measurement system utilized experimental force measuring sensors located in the pre-compression chamber to capture the forces associated with crop mass in the pre-compression chamber. Force information coupled with production baler sensor information and geographical information were combined to create estimation of mass flow and mass yield. The developed mass measurement system was evaluated against production scale systems. The performance of the developed mass measurement system was not significantly different at a 95% confidence level when compared to current production bale scale systems and successfully demonstrated mass yield estimations.