The Outdoor journal: Lumens vs. Candlepower: What's the Difference?

I was recently comparing lights that attach to the handle bar of by bicycle on a bike shop website. Some of the lights listed the number of Lumens and some just said for example, 80 candlepower.  Since outdoors folks also shop for headlights and flashlights, this seemed like an appropriate subject to explore. What’s the difference in the two? Here’s what I found:

These two measurements are determined in different ways, making it confusing to many people who are comparing lighting products. Read on to learn more about the difference between lumens and candlepower.

What is Candlepower?

Now an obsolete term, “candlepower” originally referred to a candle’s luminous intensity in a particular direction; in short, it measured the light’s concentration. Today, we use “candela” to refer to that measurement. Spotlights are commonly measured by candlepower; for instance, a light with a candlepower of 10,000,000 means it emits the equivalent of 10 million candles.

What are Lumens?

Lumens is the modern measurement of a light source’s brightness, or how much of its energy is converted into light. It is also used to determine a light source’s efficiency., for example, are flashlights, for example are measured in lumens.

Lumens vs. Candlepower

Candlepower and lumens measure different light qualities, and 1 candlepower equals 12.57 lumens. When measuring lumens, you can also think of it as the light illuminated in a 1-square-foot area one foot away from a single candle.

How to Compare Lights Measured by Lumens or Candlepower

When you’re comparing different lighting products, it’s important to consider how you’ll be using that light source. For instance, if you’re looking for an energy-efficient light that illuminates a large area, consider lighting with a high lumen rating. However, if you need a light that provides an intense beam, you should consider a light source’s candlepower instead.