Difference Between Lumens and Candlepower

If you are shopping for a handheld light whether it be a flashlight or spotlight, you will notice that the packaging will use terms like lumens or candlepower to measure the brightness of the light generated.  However, what do the terms lumens and candlepower actually mean and how are they related.

Candlepower

The term candle power is most commonly used when describing spotlights.  Candlepower is the measure of radiance produced by the light at its source . As the name suggests it is a measurement based on the light produced by a single candle.  For instance, a 2 million candlepower spotlight creates the equivalent radiance of 2 million candles at its source.

Lumens

Lumens is commonly used when describing the brightness of flashlights and now even spotlights.  Lumens is a measurement of the light that illuminates an area. It is based on the illumination of a 1 square foot area one foot away from one candle.

Comparing Lumens and Candle Power

A simple formula exists for comparing candlepower against lumens.  To determine the lumens in multiply the candlepower by 12.57 or rather 1 candlepower equals 12.57 lumens.  To determine the candlepower, dived the lumen by 12.57.

Ex:  A 2 million candlepower spotlight equals 25,140,000 lumens. While a flashlight with 150 lumens will equal 11.93 candlepower.