This paper discusses the design and testing of a new accelerometer calibrator that will be used to calibrate United States Primary Standard Transducers at the U.S. National Bureau of Standards, Gaithersburg Maryland. Accelerometers are currently calibrated by mounting them to the moving coil of an electrodynamic exciter and driving it with a sinusoidal signal of known frequency. The amplitude of oscillation is measured using laser interferometry techniques. Knowing the frequency and amplitude of oscillation, the acceleration can be determined and the sensitivity calculated. The uncertainty of the existing system at the NBS is ±1.0%, the double amplitude displacement is 7.4 mm (1 7/8 in), and the bandwidth is 2 to 49 Hz. In this paper, the design evolution and component selection reasoning for a new calibrator is presented. A new calibrator was designed and built using the following components: linear air bearing with 0.5 m (20 in) travel, linear brushless DC motor, and laser interferometer transducer system with 2.5 nm (0.1 pin) resolution and maximum allowable slew rate of 1.8 m/s (70 in/s). The new design has the following characteristics: 0.4 m (16 in) double amplitude displacement, 0.8g peak acceleration, 1.3 m/s (50 in/s) peak velocity and 20 Hz bandwidth.