Here is the easy solution for How to Calculate Power. This is for electrical Power Calculator and not for mechanical power calculator.

The Power Formula in electricity, different depending on DC and AC circuits. There is a separate formula for Single Phase Circuits and Three-Phase Circuits.

The Power Calculation in AC and DC circuits differ only by Cos Pi value. (Cos pi means Power Factor).

The 3 phase Power formula differs by the 3 in a Single Phase AC circuits.

Power Calculations in DC circuits

 If Voltage & current are known variables

 If current & Resistance are known Variables

 If Voltage & Resistance are Known Variables

Power Calculations in Single Phase AC circuits

If Voltage, Current & Cos Pi are Known Variables

 If Current, Resistance & Cos Pi are Known Variables

If Voltage, Resistance & Cos pi are Known Variables

Power Calculations in Three Phase AC circuts

 If Line Voltage, Line Current and Cos pi are known Variables

 If Phase Voltage, Phase Current and Cos pi are known Variables

 If Resistance, Current & Cos pi are Known Variables

 If Voltage, Resistance & Cos pi are Known Variables

Cos pi 

Note : 

While entering the input use only numbers.

For example, If you are going to enter a Voltage value as 2.2kv means, enter it as 2200 v. This calculator can only take numbers as input.

The Output would be also in number format.