What Is The Difference Between Kelvin And Lumens?

Varvara May 05 2022

Watt is the past. Anyone who now buys light bulbs can no longer rely on these key figures when making their selection. The lumen number indicates how bright an LED module or an energy-saving lamp becomes.

But can you convert lumens to Kelvin? Or Kelvin to lumens? No, that's not possible! That's why there is no "Lumen Kelvin Calculator". Here you can find out what the terms kelvin and lumen are all about and why both specifications must be considered independently of one another.

What do the terms stand for?


The light color is specified in Kelvin. For example, 2000 Kelvin means warm light. 5000 Kelvin denotes a cooler, bright white light. The lower the Kelvin number, the warmer the color of the light.


Lumen is the unit of luminous flux. The number of lumens indicates the total amount of scattered light from the light source, i.e. its total light output. Today, all light sources are specified in terms of lumens. This allows you to compare all types of light sources in watts. A 60 watt light bulb has a light output of 700 lumens.

The wattage is no longer a key figure for the selection of the right light source. The lumen number indicates how bright an LED module or an energy-saving lamp becomes.

Therefore there is no Kelvin to lumen conversion. The light color basically has nothing to do with the brightness of a lamp. In principle, there are both dark and bright LED lamps with every imaginable color temperature. Therefore, a direct conversion from Kelvin to Lumen or vice versa is neither useful nor possible. 

What are the differences between Lumens and Kelvin?

LUMEN: The brightness of a 25-watt incandescent lamp is equivalent to a product of 200 lumens. 400 lumens gives the brightness of a 40-watt incandescent lamp, 700 lumens that of a 60-watt unit. With 1000 lumens you get the glow of a 75-watt lamp, with 1400 lumens you get that of a 100-watt lamp.

KELVIN: The color temperature indicates the Kelvin unit. 2700 Kelvin corresponds to the warm white light of a standard incandescent lamp. Neutral white or daylight bright lights have a higher number.

Useful conversions between lumens and Kelvins

One reason for the often assumed connection between lumen and Kelvin is the fact that cold light colors appear brighter with the same number of lumens. However, this is due to our perception and does not represent a connection between the two physical units.

With conventional light sources, on the other hand, there is a direct connection between the brightness and the electrical power consumption. There you can easily convert lumens to watts. This is particularly helpful when old lamps are to be replaced with modern LED technology. The lumen watt calculator helps to get an orientation for the required brightness of LED lamps.


You now know that there is no conversion between Kelvin and lumen. These are two physical entities that are not directly related. The Kelvin value describes the color temperature of an LED lamp. The lumen specification describes the brightness of an LED light source or a lamp.