Projector Lumens: The Definitive Guide

When it comes to choosing the right projector, the brightness of the projector is the most crucial consideration.

In this article you’ll learn:

  • What is a Lumen?
  • What is ANSI lumen?
  • How are ANSI lumens measured?
  • How many lumens do I need for a projector?
  • Lots more

Let’s get started.

Broadly speaking, the lumens of the projector is divided into several units, among which the common ones are the brightness of the light source and ANSI lumens.

What is a Lumen?

Lumen is basically defined as a measure of brightness that your device can produce.

However, you can’t simply rely on published lumens because it is the brightness that is not cut by the lens or other factors.

For example, suppose you bought a projector with a lumen of 4000 in Company A, and then your friend bought a projector with a lumen of 3000 in Company B. In terms of lumen value, the projector of Company A should look brighter, but for some reason, Company B looks brighter than Company A.

This is because Company A determines the lumen according to their own criteria and Company B determines the lumen according to their own criteria.

To solve this problem ANSI lumen comes into play.

What is an ANSI Lumen?

An ANSI Lumen is an international standard unit to measure the luminous flux of projectors. ANSI lumens is the brightness after layer-by-layer reduction. Taking the sun as an analogy, the sun itself is the brightness of the light source, and the sunlight hitting us is the brightness of the projector after being cut and projected on the wall.

It consists of measurement at nine points, as shown in the below figure. The ANSI luminance is the average of these measurements.


The ANSI lumen helps to solve the above-mentioned problems of lumens.

As a result, all manufacturers around the world adopt ANSI lumens to measure the brightness of projectors and also to maintain the same standard.

so that we can compare projectors from various companies without worrying.

How are ANSI lumens measured?

So we’ve seen what a lumen is and what an ANSI lumen is. A question that runs through your mind is: What’s the difference between them?

The main difference between ANSI lumens and lumens lies in their measurement methods.

So to measure ANSI lumen, you’ll have to follow the below steps:

1. Divide the projection surface (wall, screen, etc.) into 9 parts of 3 x 3 vertically and horizontally.

2. The average illuminance (lx) is calculated by measuring the brightness of all nine central parts of the surface.

3. Multiply the average illuminance (lx) by the projected surface area (㎡). 

Here’s how the formula looks. ANSI lumens = illuminance average (lx) x projection surface (m2).

How many lumens do I need for a projector?

Generally speaking, projectors with more than 1000 ANSI lumens will be sufficient. There is no way to give an accurate numerical estimate because the effect of the projection screen is influenced by factors such as the brightness of ambient light, projection distance, and projection size.

Final Thoughts

I hope I’ve given you a greater understanding of projector lumens overall. Other than that you should also pay attention to the resolution and contrast. These are all factors that affect the picture quality.

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