Given an Arduino board with the following specs:
ATmega328 Arduino Nano AVR® ATmega MCU 8-Bit AVR Embedded Evaluation Board (link)
What is the mathematical formula to calculate how much energy/power would be required to keep the Arduino board on (meaning in "standby" mode, therefore not consuming any energy but the one required to keep it "alive")?
Please note I am new to all things electronics, Arduino but most importantly physics and maths. Thank you.