A treadmill may comprise a drive motor positioned and configured to drive a treadbelt, and an electrical current sensor configured to measure the electrical current utilized by the drive motor. The treadmill may also include a computer programmed and configured to analyze the measured electrical current usage by the drive motor to determine the weight of a person positioned on the treadbelt. A person's weight may be determined by driving the treadbelt with the drive motor while a person is positioned on the treadbelt, measuring an electric current utilized by the drive motor, and analyzing the measured electric current to determine the weight of the person positioned on the treadbelt of the treadmill. Additionally, the measured weight may be utilized to calculate calorie expenditure.