Since different brands and models of digital scales require different calibration methods, the only way to perform a completely accurate calibration is to follow the manufacturer's guidelines. Exact calibration procedures are located in the scale's instruction manual or on the manufacturer's website.
Calibrate digital scales on a weekly or monthly basis, depending on usage, and after replacing batteries or moving the unit. A digital scale’s accuracy can be confirmed without performing a calibration, by weighing items with confirmed weights, such as canned goods, bags of sugar, or new coins. Only test accuracy with items that do not exceed the scale’s weight capacity. Digital scales must be used on a non-moving, flat surface and kept at room temperature to perform properly.