Voltmeter is a measuring instrument used to measure the difference in voltage between two points in the electrical network. In general, there are two types of voltmeters - is an analog voltmeter and the other is a digital Voltmeter. In analog voltmeter a cursor moves on the scale to represent the voltage. digital Voltmeter displays directly the voltage figures with the help of analog-to-digital converter. This article describes how to design a digital Voltmeter into two methods 1) using microcontroller 8051 and 2) one using IC L7017.