Currently there is no legislation in place to define the time period to Calibrate scales. Your scale usage, the environment in which they are used and the scales required accuracy are all major factors when considering how often to test their accuracy. Testing scales more often will help ensure accuracy. Based on usage some scales may require yearly or monthly tests while others like Super Markets may have daily spot checks in place. We recommend testing and calibrating your scales at least every 12 months to ensure accuracy.