Lux vs. Lumens Projector – A Guide on Projector Brightness

With consumers becoming more and more sophisticated, there’s the need for a deeper understanding of product specifications. It is true, especially with consumer electronics, including projectors. Knowing what the terms meant is crucial, given the endless variations when it comes to quality, features, and prices of these products.

In the home theater market, one aspect consumers need to understand more is the brightness. When you know the different units of light involved in ensuring your projector provides greater clarity, you can make an informed decision. On that note, let’s compare lux vs. lumens projectors and find out more about projector brightness.

The term ‘brightness’ used here is subjective and not used in optics. When discussing light, experts typically use “luminance.” But in this article, we try to make it simple and easy to understand.

Units of Measuring Light in Projectors and Home Theater

There are several terms or units to measure light when it comes to projectors. They include lumens, lux, nits, foot-lamberts, and ANSI lumens.

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Lux vs. Lumens

Lumens and lux are both Si-based units. Lumens measure luminous flux, which is the total amount of light a light source produces per unit of time. You might confuse luminous flux with radiant flux, but they are different. Luminous flux measures electromagnetic waves only visible to the human eye, not from all sources.

It measures the total number of quanta or packets a light source produces. A lumen is a luminous flux that a light source of one candela of intensity emits over a solid angle of one steradian. It is also the unit of measurement used for the light outputs of a projector as well as other lighting equipment, i.e., lamps.

On the other hand, lux is the unit used to measure brightness in terms of surface area. When it comes to projectors, it refers to the lumen per square meter. It measures how much incident light illuminates a surface, indicating how a human eye perceives light intensity. With this, the spread of an area’s effect on luminous flux is to be considered.

Lumen and lux are closely related to each other, measuring the illuminance of a light source but in two varying contexts. It means that a lumen is the amount of light from light sources, taking human eye sensitivity to account. Lux is how bright a light appears after considering how it spreads over an area.

If you measure them from a fixed source, the lumens should have a constant number while the lux decreases as the distance increases. As you can see, these two measures of brightness are crucial when you look for a projector. It helps you invest in a projector that will output enough light for a clear image, no matter the distance.

Lumens vs. ANSI Lumens

There are numerous specifications and features you’ll want to evaluate before buying a projector. Of them, one of the often misunderstood is the lumen quality. From the explanation above, you realize that it refers to the brightness the projector produces. Lumen is crucial as it affects the image quality displayed by the projector.

In terms of lumens, one of the things that confuse people is ANSI lumens. Some projectors list this, which is much more accurate compared to lumen observation. With ANSI lumens, the luminous flux is measured through more meticulous methods with more variables involved.

Older projectors usually only include lumen measurement, but they are often inaccurate. Newer projectors such as those used in home theaters provide ANSI lumens. It is much more realistic and quantifiable. With this, the information you obtain is more reliable when you decide to invest in a particular projector.

What is the Best Way to Measure Projector Contrast Ratio?

Number of Lumens a Projector Needs

Choosing a projector in terms of brightness depends on how you will use it. On that note, you have three things to consider. These factors are the content, ambient light, and resolution. The cumulative assessment of these factors will give you an idea of the number of lumens your projector should have.

The content or material you plan on projecting affects the number of lumens you need. A business projector used for presentations needs fewer lumens. But if you will need it for your home theater system, the number of lumens varies.

  • Business /Portable – A minimum of 1500 lumens is enough for business and personal use.
  • Home Theater – A minimum of 2000 lumens for a projector to be used in projecting television shows or movies.
  • Gaming – A minimum of 2000 lumens is ideal if you plan to use the projector mostly for gaming.

If you only need a projector for work or school work, then 1500 lumens is good enough. But if it is for a home theater, then you should start at 2000 lumens no matter the other factors. It should increase after you considered other specifications like the lux, throw ratio, contrast, input capabilities, etc.

Besides the content, you should also keep in mind the resolution. With home theaters, the common resolutions are 1080p and 4K. Gaming platforms often use 1080p resolutions. As for most portable projectors, they usually only have 840 x 480 resolutions. These things matter along with the lumens as they will ensure the projector provides you a clear image.

Don’t forget about the ambient lighting. The environment where you will project has a significant impact on choosing lumens. It directly affects brightness, after all. As for the ambient light, consider the screen size as well. These two will affect how much lumens you need to make sure your projector has enough brightness for excellent viewing.

Here is a short video of the difference between lux and lumens if you’re still confused.


Comparing lux vs. lumens projector is not exactly right. They refer to two different things, so a comparison of them is quite useless. They do relate to each other, but only in that they both measure the brightness produced by a light source. When choosing a projector, it is the lumens that really make a difference when in terms of brightness.


  1. The Different Units of Brightness for Projectors: Lumens, Lux, Foot-Lamberts, Nits, and ANSI Lumens, BenQ,, April 3, 2020
  2. Difference Between Lux and Lumen,, February 23, 2013
  3. Projector Lumens: A Complete and Accurate Guide!, Jonah Matthes,
  4. Home Many Lumens Do I Need For a Projector | Perfect Guide, Michael John,, June 10, 2019

James Core

I love my projector system and I am here to help you find the right projector for your needs.

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