How Many Lumens Do I Need?

Almost all modern lamp specifications include a lumen value. This indicates how much light the lamp emits. In the past, wattage was the primary measurement used, but today, wattage alone no longer provides a clear indication of brightness. So, how does it work?

What Does Lumen Mean?

Lumen (lm) is the unit of light output, measuring the total amount of visible light emitted by a lamp. The term "visible light" is important because some lamps also emit infrared light or heat, which are not considered in lumen measurements.

When most lamps were incandescent bulbs, brightness was expressed in wattage. However, with the introduction of various types of lighting, we now use lumens as the standard. This makes it easier to compare different types of lamps (halogen, LED, and CFL). Wattage only represents the electrical power consumption of a lamp and no longer accurately reflects brightness. For example, a 50-watt halogen lamp does not emit the same amount of light as a 50-watt LED lamp.

Comparing Lumens to Watts

To make the transition to lumens easier, we compare the light output of a lamp in lumens with the wattage of an incandescent bulb. For example, a LED bulb packaging might state that it emits 470 lumens, equivalent to a 40-watt incandescent bulb. The table below compares the number of lumens to the corresponding wattage of an incandescent bulb.

How Many Lumens Do I Need?

This table applies mainly to general-purpose bulbs that emit light in all directions but does not apply to spotlights. Spotlights produce a more focused beam, meaning they require fewer lumens to illuminate a specific area effectively. However, a spotlight only covers a small area, whereas a general-purpose bulb illuminates an entire room. The number of lumens you need depends on the beam angle of the lamp.

To give an idea of light output in lumens: an 800-lumen lamp can easily light up a room. A table lamp typically produces around 200 lumens. Several accent lights combined should not exceed 100 lumens each. However, the required lumen output depends largely on the placement and intended use of the light. If a fixture is mounted high up, you will need a higher lumen output to achieve adequate illumination compared to a desk lamp. This is why testing different lighting options or creating a lighting plan can be beneficial.