The paper proposes the development of an IoT measurement system that offers the user the possibility to monitor and record the electricity consumed by a consumer through the Blynk application. In monitoring electricity one of its most important aspects is the calibration of the sensors used. Accurate and reliable detection is the key factor in measuring and managing electrical equipment. Fundamental physical quantities such as voltage and current are useful for determining all other electrical quantities. The ESP32 development board used to develop the system has 18 channels ADC (analog to digital converter) and supports a Wi-Fi connection at the access point and implicitly to the internet. The developed system can measure the voltage (U), current (I), power consumption (W) and consumption / hour (kWh) of a consumer, in my case for the consumer I used a light bulb with a power given by the manufacturer of 10W. The measured values are displayed on the LCD display of the system or through the Blynk application which also allows the registration of these values for a period of 12 months.