Lumens are a measurement of brightness, while watts tell you how much energy the bulb consumes as it burns. LEDs—which are much more energy-efficient than incandescents—are labeled with output (lumens) rather than energy usage (watts). As a guideline for choosing bulbs, here’s how the two compare: 40 watts = 450 lumens 60 watts = 800 lumens 75 watts = 1100 lumens 100 watts = 1600 lumens 150 watts = 2600 lumens