Lux vs Lumens: What Are the Differences?

Lux and lumens are two different ways of measuring light. They measure the same thing, but in a different way.

Lux measures how much light is falling on an object per square meter, whereas lumens measure total emitted light from one point.

Before we are going further, we’ll explain some basic concepts so you can understand them better. Let’s get started!

 

Terms You Need to Know Before Reading

1. What is Lux?

what is lux vs lumens

Lux is a metric unit of illuminance in which one Lux equals one lumen per square meter.

It measures the amount of light that falls on an object and gives it the ability to produce a detectable, perceivable difference between two identical surfaces lit by different amounts of light.

2. What are Lumens?

Lumens is an international unit for measuring luminous flux, a quantity representing the total amount of visible light emitted by a source, such as a star or a bulb.

3. What is foot candle?

Foot-candle is a unit of measure for illumination perceived by the eye. It’s formally referred to as ‘lumens per square foot.

In other words, it’s based on the brightness a surface (such as your living room) will be illuminated by just one standing candle.

4. What is candela?

Candela is a standard measure for the luminous intensity of an object. This means how bright it appears to your eyes.

Luminous intensity is measured on the candela scale, and it quantifies how much energy comes off as visible light from an object per unit of projected area.

 

Relation between Lux and lumen

Lux and lumens are two different ways of measuring light.

One difference between Lux and Lumens is that lumen measurements are based on the intensity of emitted radiation, which accounts for factors such as distance from the source or reflectivity of the surface being lit.

On the other hand, Lux measurements are based primarily on one’s ability to see well in that environment.

 

Difference Between Lux and Lumens

lumens vs distance chart

Lux is the unit of measurement for illuminance on a perfectly diffuse surface.

Lumen measures luminous flux or amount of light.

In other words, a lumen’s spectral content changes based on where it comes from, whereas the color and intensity of light emitted from a lux do not change depending on its fixture or spectrum.

In addition, lumens are typically measured in what we call “foot-candles” that can be traced to one particular point, while levels of illumination expressed as Lux have infinite points of origin.

Lastly, Lumens measure how much total light is received by your eyes from the source, while Lux measures how much total brightness there is at one location.

 

When to Use Lux vs. When to Use Lumens

Lux and Lumens are two measurement units for the light which can be confusing.

The best way to think about it is that Lux measures the intensity of a beam of light, while lumens measure how much light is being emitted from a source.

To put it even more simply, if you want to determine how much illumination an object will get from either lamp, then look at the lumen measurements.

If you want to see how bright an area will appear with those lamps turned on in contrast to other lights present, then look at lux measurements instead.

As a rough rule of thumb, if you have a medium or low light space, such as an office setting, use Lux; if the amount of natural light in your space is high, such as in an open-concept living room with large windows, use Lumens.

 

Lux to Lumens Conversion

The lumen is the standard unit of luminous flux in photometry, which quantifies the perceived brightness of a given light source.

The Lux was originally designed as a measure for illumination intensity.

A function of lumens per square meter specifies how much brightness will be cast on an object at any given distance. One Lux is equal to one lumen per square meter.

Lumens Chart

For a 50 square meter room, 500-1000 lumens are required.

You can use this information to see how much wattage is needed for a certain amount of space by looking at this chart:

Bulb | Brightness450 Lumens800 Lumens1100 Lumens1600 Lumens2600 Lumens5800 Lumens
LED6W9 – 10W13W16-18W24W45W
CFL8-9W13 – 14W18 – 19W23W4085W
Regular Incandescent40W60W75W100W150W300W
Halogen29W43W53W72W150W300

 

How Many Lumens do I Need?

The amount of lumens you need also depends on your usage and brightness preference. The brightest light bulb is 5800 lumens, but many people prefer warmer 3000-3500 lumen LED bulbs that provide more than enough light for a living room or reading without being too bright when close to the eye.

If you plan to use the light for task lighting, you might want 3000 lumens as well because this will give better-directed illumination of the task at hand and keep shadow falloff to a minimum.

 

FAQs

1. Are Lights with More Lumens Brighter?

Yes, technically. Lumens are a measure of brightness; the higher the number of lumens, the brighter they appear.

2. How many lumens are considered bright?

Bright is subjective, but generally, anything over 100 lumens is going to be pretty bright.

The lumen measure indicates how many times brighter the object appears than it would if there were no light source.

3. How many lumens do I need in a storage room?

For storage, you don’t want to need a lot of light. A basic rule of thumb is about 20 lumens per square foot.

For a small storage room, 100 lumens should be just about sufficient. For medium-large storage rooms, you’ll need something closer to 500 or 800 lumens.

4. How many lumens does a bathroom need?

It’s best to select a bathroom fixture that offers between 500 and 800 total lumens to give you the best balance between lighting power and energy efficiency.

 

Conclusion

For most people, the difference between Lux and lumens is a mystery.

It’s understandable. The way that these two measurements are used can be confusing at best and misleading at worst.

Lux is a unit of illumination, which measures how much light falls on a surface in all directions. Lumens are units of luminous flux, which measure visible light only.