Use this calculator for checking the power and electricity consumption of your air conditioner. This calculator is specific to the indian region.
Using this you can calculate values for both inverter or normal air conditioner.
Formula Used here
Power = ( Cooling Capacity / ISEER Rating ) * 0.75
Why 0.75 is multiplied ?
Compressor does not run at max power always. In case of normal AC the compressor runs only for 75% of time while in a inverter AC compressor runs at 75% of max power.
This assumption is only true when AC works in a room whose set room temperature is achieved and after that, the AC only maintains the room temperature
Other wise the power consumption and eletricity bill will be higher. Just remove the factor of 0.75 from power calculation.
Read this to know how to calculate power consumption of any AC.