Lux vs Lumens - Everything You Need To Know

There’s a lot of terminology when it comes to lighting. From IP ratings to lumen outputs, it can be a challenge to figure out what kind of bulbs you need to illuminate your home properly. There are two measurements used to calculate light output: lux and lumens. We’ll explain the difference between the two and how you can use them to choose the right kind of lighting for the different spaces in your home. 

What Is a Lux?

A lux is the level of illuminance you get from a light, calculated by how bright a light is along with how close it is to a given flat surface. It can also be defined by the number of Watts per square metre. 

What Are Lumens?

Lumens are the more common unit of measurement when looking at light bulbs and globes. Lumens refer to the measurement of visible light that’s perceived by the human eye - regardless of the direction it’s pointing in. 

When you’re exploring LED globes, our product descriptions list the lumens, making it easier for you to choose the right one. Lumens are a more crucial factor for choosing the right lighting because they correlate to how your eyes actually experience light. 

How Many Lumens Are In a Lux?

When you’re calculating how bright a room needs to be, there isn’t a specific conversion between lumens and lux because they measure light differently. However, one lux equates to one lumen per square metre of space. 

What is the difference between Lumen and Lux?

Lux and lumens measure light differently. Lux measures intensity, while lumens refer to the actual light output. Lumens are a source's light output and how much energy comes out of the energy passing through a light bulb, while lux refers to how brightly a surface will be illuminated based on the energy going into creating that light. 

When to Use Lux vs Lumens?

Typically, lumens are used to check how bright something will be when installed in your home. Lumens refer to the overall lighting capability and how it will disperse over the room. How many lumens you need for your home will depend on the function of any given space. For example, you need more lumens per square metre for working areas like the kitchen and office, while places like the bedroom and living room can feel too clinical with a lot of bright light, so you’d drop the number of lumens you need. 

You’d use lux more if you were looking at lighting up a specific surface. Lux is the intensity of light directed towards a given area. For example, projectors and spotlights are made to create specific, focused light that refers more to lux output. The distance the light has to travel, along with how bright the light itself will be are the two factors that dictate how intense that light will be. A lux measurement will differ when it’s placed two metres away from a wall compared to five metres away from the wall due to the relative perception of how bright it looks. 

In a home context, you might use lux to calculate how brightly lit up a workspace is, while lumens refer to the ambient light that spreads across a room overall. 

How to Measure Lux vs Lumens

While lux and lumens are both units of light measurement, how they’re measured is different. Lux measurements require a light metre, and lumens require a photometer to calculate overall light dispersal and illumination. 

Using Lux vs Lumens

Most of the time, you’d calculate how many lumens you need to light up a room from sources like ceiling lights or floor lamps. Lumens are the ambient light that spreads across a room. You’d use lux if you were trying to calculate how much light you need to brighten up a specific work surface - for example, if you have a table lamp on a desk. 

If you need help finding the best lighting solution for your space, our team is more than happy to help. You can contact us any time for guidance on proper illumination, along with recommendations for which lighting solutions will be best for your home.