People often get confused about the calibration process of the calipers. Before the equipment falls out of tolerance, you have to do the calibrating process. In most cases, the calipers require calibration once every 12 months. But keep in mind that if you calibrate the calipers in shorter intervals, you will get better specifications. This also depends on how often you use your calipers. In that case, you can calibrate the calipers monthly, quarterly, or once a year. If you better you check the manual of the caliper to know the calibration period.