The English system of units that has dominated the United States from historical times is now being replaced by the SI system of units. Major industries throughout the United States either have already made, or are in the process of making, the transition, and engineering students and teachers must deal with the new SI units as well as the present English system. We present here a short discussion of the SI units as they apply to the vibration field and outline a simple procedure to convert from one set of units to the other.