BRIGHTNESS (LUMENS) measure the amount of light produced, whereas watts measure the amount of energy required to light products. Simply put, the more lumens in a light bulb, the brighter the light. Lumen measurements are needed when comparing LED bulbs to other light sources. Shopping by lumens is how you determine the brightness of your bulb. The chart below shows the lumens values for common incandescent bulbs:

Watts Lumens
40-watt incandescent bulb 450 lumens
60-watt incandescent bulb 800 lumens
100-watt incandescent bulb 1600 lumens

LUMENS & DIRECTIONAL LAMPS. While lumens can be a guide to measure directional lamps, they do not tell the full story. Directional lamps are measured by the amount of light that gets to the surface you are lighting. This measurement is called foot candles. Directional lamps can come in different spreads—flood, narrow flood, and spot, to name a few. The light that is on the surface will look very different depending on the spread, but the lumen output can be the same.