What is the power rating of smart phone charger? All Questions › Category: Electrical Estimating And Costing › What is the power rating of smart phone charger? 1 Vote Up Vote Down Chetan Shidling Staff asked 4 years ago I need short information. 1 Answers 0 Vote Up Vote Down Chetan Shidling Staff answered 4 years ago 2.5 to 5 watts is the power rating of a smartphone chargers.