A watt is the unit of measurement for the amount of electricity a light fixture uses. When you’re talking about incandescent light bulbs, this term is commonly also used to express brightness, even though watts don’t tell you anything about how bright a light is. “Lumens” is the measure of brightness. With our LED lights, the wattage always means simply how much power is used. A typical 40W light bulb draws 40 watts of power and gives off about 300 lumens of brightness, while an LED bulb of 300 lumens might use about 6 watts.