Is 9500 lux a lot for a projector?

On its own the number means nothing, because no screen size is stated. To actually put 9 500 lux on a 100-inch screen you would need roughly 26 000 lumens — far beyond any home projector. The figure was measured very close to the lens.

Why do cheap projectors advertise lux instead of lumens?

Lux gets larger the closer you measure, so an unqualified lux figure can be made to look impressive without stating an ANSI lumen number that could be checked.

How many lux do I need on my screen?

Roughly 150–200 lux for a dark room, 350–500 for a living room with some light, and 700+ where daylight is a factor — which is the same advice as the lumens guide, expressed per square metre.

Are lux and ANSI lumens ever the same?

No, they are different quantities. ANSI lumens measure total output on a standardised nine-point average; lux measures illuminance at a point. Only the conversion above relates them.

Lux vs lumens: what a projector's lux rating means

Guide

Lumens measure the total light a projector puts out; lux measures how brightly that light lands on a surface, and it falls off as the image gets bigger. A “9500 lux” claim is illuminance at some small, unstated distance — it is not comparable to a lumen figure. To convert: lumens = lux × screen area in square metres. On a 100-inch screen (2.76 m²), even a genuine 3 000-lumen projector delivers only about 1 090 lux.

The two units answer different questions. Lumens describe the projector; lux describe a particular spot on a particular screen at a particular size. Because a bigger image spreads the same light over more area, lux drops as you zoom out — which is why a lux number without a stated screen size or distance tells you nothing. Sellers quoting four- and five-digit lux figures are usually measuring inches from the lens. Do the conversion yourself: divide the claimed lux by the lux the table below shows for your screen, and you get the lumens implied.

What a projector's brightness gives you, in lux

Screen	Screen area	1 000 lm gives	2 000 lm gives	3 000 lm gives
60″	0.99 m²	1010 lx	2015 lx	3025 lx
80″	1.76 m²	565 lx	1135 lx	1700 lx
100″	2.76 m²	365 lx	725 lx	1090 lx
120″	3.97 m²	250 lx	505 lx	755 lx
150″	6.20 m²	160 lx	320 lx	485 lx

Frequently asked questions

Multiply the lux figure by the screen area in square metres: lumens = lux × m². A 100-inch 16:9 screen is 2.76 m², so 500 lux on it means about 1 380 lumens.

Calculator →Throw distance by screen size →Projectors →

Related guides

Guides

ANSI vs ISO vs LED lumens

ANSI and ISO 21118 lumens are measured the same trustworthy way (averaged across the image) and are roughly equal. CVIA is a reliable newer standard. "LED lumens" and vague "marketing lumens" are inflated — often 2 to 3 times the real ANSI figure. Always size brightness by the ANSI or ISO number.

Guides

How many lumens do I need?

Lumens needed scale with screen area and ambient light. As a rule of thumb, a 100-inch screen needs about 600 lumens in a fully dark room, around 1,300 for a living room with some light, and 2,700+ for a bright room. Bigger screens and more light need proportionally more.

Guides

Projector screen gain explained

Gain is how much light a screen reflects back compared with a reference matte-white surface, which is defined as 1.0. A 1.5-gain screen sends about 50% more light toward the centre seat; a 0.6-gain screen sends 40% less. The counterintuitive part: **most ambient-light-rejecting screens have gain below 1.0**. Across the 24 ALR and CLR screens we track, 15 of them — 63% — are darker than plain white. CLR screens for ultra-short-throw projectors sit around 0.6. They buy contrast by rejecting light from the sides and ceiling, and they pay for it in brightness, so they need a brighter projector, not a dimmer one.

Updated October 19, 2026