To calibrate your multimeter, you will need to follow these steps: First, you must set the function switch to the “DCV” position. This process ensures the multimeter is providing reliable and accurate data. There are two reasons why you would want to calibrate your digital multimeter. Digital multimeters have at least five functions, with many ranges per function; the calibration procedure needs to confirm that the DMM is suitable to use through this full range of capabilities. Here's a general guide on how to calibrate a multimeter: Gather necessary equipment, including a calibrated reference standard multimeter, calibration sources (e.