Charger wattage, measured in watts (W), represents the charger's power output. It's a critical parameter that determines how quickly your device charges. A charger's wattage is calculated by multiplying its voltage (V) and current (A) ratings. For instance, a charger with a voltage rating of 5V and a current rating of 2A has a wattage of 10W (5V x 2A = 10W).