The Balance Tracking System (BTrackS) is a low-cost force plate that has been introduced as a balance-testing device that can rival its counterparts in the clinical and rehabilitation domains. Due to the cost of traditional force plate devices, the most widely used assessments of balance are limited to subjective visual tests such as the Balance Error Scoring System (BESS). BTrackS has been offered as a device that can provide a portable, objective, accurate, and reliable balance test at a fraction of the cost of a "gold standard" laboratory-grade force plate. Although some static research has been done on the BTrackS, a dynamic test is needed to prove that this device is a valid and reliable center of pressure (CoP) measurement device. The purpose of this study was to validate the BTrackS ability to measure dynamic postural sway with an inverted pendulum model. In order to validate dynamic postural sway an inverted pendulum model was placed on the BTrackS and on a "gold standard" AMTI force plate simultaneously. The pendulum was then displaced at six different displacement angles (1.5, 2, 3, 4, 5, 6 degrees) in anterior-posterior (AP) and medial-lateral (ML) directions with a total of 120 trials. Two different BTrackS were tested to assess the inter-device variability of the product. There was no significant difference in measurement error between the AMTI force plate and two BTrackS devices, which showed small inter-device variability. With such results, it can be said the BTrackS is a valid alternative to a laboratory grade force plate.