Watts measure the amount of electricity a light bulb consumes. In lighting, they indicate power usage, not brightness.
Before LED bulbs became common, wattage served as a rough guide to how bright a bulb would be. A 40 watt bulb gave off a soft glow, while a 100 watt bulb produced much more light. That connection worked because incandescent bulbs were inefficient, using more energy to create brightness.
Modern lighting changed that relationship. LED bulbs use far less electricity to produce the same amount of light. For example, a 9 watt LED can deliver brightness comparable to a traditional 60 watt incandescent bulb. The wattage drops dramatically, but the light output stays similar.
Today, watts are best understood as a measure of efficiency and operating cost. Lower wattage means less energy consumption, reduced heat output, and often a longer lasting bulb. This makes LEDs both practical and economical for everyday use.
When choosing lighting, lumens tell you how bright the light will be, while watts tell you how much power it will use. Together, they give you a clear picture of performance and efficiency.
In short, watts are about energy. They do not determine brightness. They simply tell you how much electricity the light requires to operate.