Projector Lumen Guide

Last updated on January 15th, 2020 at 02:38 pm


Projector Lumen guide: Introduction 

Understanding projector jargon is the first step in transitioning from projector to TV. One of the first confusing terms to arise is “Lumens”. It can be a daunting and unfamiliar term, which is why our projector lumen guide is sure to help you out.  

Upon purchasing my first projector, I had no idea what this meant. What made it especially confusing was the complexity of explanations sites used in order to help with my understanding. 

This makes it easy to see why a lot of first time buyers go for the highest lumen rating and assume that will suit their needs. Of course, this isn’t the case and often going for the highest lumen rating alone isn’t going to satisfy your projection needs. 

Dim bulb

What are “Lumens”

A Lumen is the measurement of visible light that comes from a source per unit of time. In simple terms it is the output of light from your projector. The higher the lumen count of your projector, the more light is emitted. 

It’s easy to assume that lumens therefore are a measure of brightness. However brightness is a perception. Lumen(s), on the other hand, is the intensity of light coming directly out of the projector onto the screen. 

Summary: Lumen is the measure of light from your projector.

Measuring Lumens 

Lumens become pretty difficult to accurately measure and compare. This is mainly due to the different methods of retrieving a “lumen count”. It’s important you’re aware of which type of measurement a projector is referring to when making your selection. 

Lumens are measured in 3 ways:

  • ANSI Lumens
  • Center spot Lumens 
  • LED Lumens

ANSI lumens 

ANSI lumens refer to a standardised method of understanding a devices true Lumen level. It takes into consideration different factors, such as contrast, screen size and an average measure of projected brightness. 

Instead of taking one spot measurement from a screen, ANSI lumens equally divide the screen by 9 and take an average. 

ANSI projector Lumen measurement
How ANSI average is taken

As if this wasn’t complex enough, not all lumen ratings you come across will refer to an ANSI lumen count. When comparing the lumen counts of different projectors, it’s important you’re using the same format in order to form an accurate comparison. 

Summary: ANSI is a standardised approach to measuring lumens and the most accurately comparable. 

Marketing Lumens

The following Lumen measurements are often referred to as “marketing lumens”. These are Lumen ratings that although not inaccurate, bend the truth a little in order to become more marketable. 

Often in comparison to ANSI readings, the ratio comes in at 6:1. That is, every 1 ANSI reading is roughly transferable to 6 “Marketing Lumens”. 

Center spot Lumens 

Although this count will also be referred to as “Lumens”, the method used to measure differs to ANSI. 

Center spot readings take one measurement from the center of a screen as opposed to an average. The center of the screen will always have the highest level of brightness. This is because as light disperses from the center, it loses its strength. 

Of course, this means that a center reading is often higher than an ANSI reading (and not entirely accurate). 

Center Projector Lumen measurement
Black spot: Where the measurement is taken

Summary: Center spot Lumen only measures the brightness in the center of the screen. This makes the Lumen rating a lot higher.

LED Lumens 

LED Lumen rating gets a little bit more complex. 

Due to the colour saturation offered in LED and Laser projectors, we perceive brightness to be higher than it would measure at. This is something called the Helmohltz-Kohlrausch effect.

When Manufacturers refer to an “LED Lumen rating” they’re referring to the perceived brightness. That is, they will use the Lumen rating for a lamp based model with the same perceived brightness. 

However, whilst lamp projectors perceived and actual brightness is the same, LED perceived brightness and actual brightness differs. 

This means that the ANSI Lumen level will read at a lot lower than the given LED Lumen count. Of course, the LED Lumen count is a lot more marketable than the ANSI lumen count, hence

its use. 

LED light
LED brightness example

Summary: LED Lumen count is a measure of perceived brightness as opposed to actual brightness. 

Note: throughout the rest of this article all reference to Lumens will be in ANSI format. 

The importance of Lumens 

The Lumen rating of your projector is one of the most important factors to consider when buying a projector. If you’re unsure of what else to consider, check out our projector buying guide

There are a multitude of external factors that are important to consider when selecting a Lumen rating:

  • Ambient lighting 
  • Content consumed 
  • Projector use 

Ambient lighting 

Ambient lighting refers to all other light sources other than your projector. This could be in the form of natural or artificial light. 

Of course, in an ideal world we would have full control of this light. However, more often than not our projectors are in uncontrolled environments. Examples of these are classrooms and business meetings. 

Because projected images are a reflection of light, having high ambient lighting conditions makes the image dull, less saturated and harder to see. 

To combat this, it’s important to have a higher Lumen rating on your projector.

Screen size

Your desired screen size is going to have an impact on the Lumen rating you will need. Of course, the bigger the screen, the more light needs to be dispersed to create it. This means the Lumen rating needs to be higher to compensate for this. 

The most popular screen sizes fall anywhere between 100-120 inches, however you are by no means limited to this. 

The figure you should take into account when selecting your projection side should be dictated by the “maximum optimal projection size” advertised. Anything over this will start to compromise on your image saturation and colour representation. 

Projector lumen rating
Correct Lumen rating V.s Low Lumen rating

Recommended minimal ANSI Lumen 

(screen size between 100-120 inches diagonal)

Lighting conditionMinimum ANSI  Lumen rating Maximum ANSI  Lumen rating 
Home theatreCompletely dark20002300
Home theatreSomewhat dark23002500
Home theatreBright25003000
Business meetingVery bright30004000
Hall or auditoriumSomewhat dark4000

Going over the Maximum recommendation

The above figure mentions maximum recommended Lumen count. Going over this figure isn’t going to impact your projection ability, only your comfort levels. 

When we look at a backlit object for too long, our eyes can start to get tired (especially in dark surroundings). This is because our pupils expand due to the external lighting and don’t take into account the light from our screens. As such, bright light enters the eye when it’s expecting lower level lighting conditions. This can lead to eye fatigue over time. 

Although not a huge issue, if you plan to spend a lot of your free time using your projector, it can become annoying. 

What type of Projectors have the highest Lumen potential 

Different types of projectors have different Lumen outputs. For example, an LED projector isn’t going to have the same Lumen potential as a laser projector. 

In general, LED projectors have the lowest potential Lumen output due to their energy saving capabilities. This is why many LED projectors use a “perceived” lumen count as opposed to ANSI. 

Following this, Lamp projectors usually produce mid-range Lumen output. Of course, this varies depending on the type of bulb used by the projector. However, lamp based projectors have the same perceived and measure Lumen count (although ANSI and center spot ratings still differ).

Laser projectors produce the highest Lumen rating. Most Laser projectors come in at over $2000 and are specifically designed to be used in high ambient lighting conditions.  


Lumens are perhaps the most complex and important aspects of projectors to understand. Having a correct Lumen rating is going to ensure that you buy a projector that is able to accurately and comfortably depict your content. 

There are plenty of other factors to consider alongside projector Lumen capabilities when making a purchase decision. To help you figure them all out, check out:

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