Brightness is measured
LED and CFL bulbs measure a bulb's brightness in lumens, not watts.
Select a wattage to view its lumen equivalent
What to Look for on the Package
To help consumers better understand the switch from watts to lumens, many packages include a product label for light bulbs. It helps you buy the light bulbs that are right for you.
Like the nutrition label on food products, the Lighting Facts label helps you understand what you are really purchasing. The label clearly provides the lumens -- or brightness -- of the bulb as well as the estimated operating cost for the year, and the colour of the light (from warm/yellowish, to white to cool/blue).