> BRIGHTNESS CALCULATOR
Brightness calculator
Work out the lumens your screen size and room light actually need.
Before you buy
What this calculator works out
Brightness is the specification most often misread, because screen size changes the answer as much as the room does. The same projector on a 150 inch screen delivers less than half the light per square foot it does on 100 inches. Give us the size, the light and the screen type and we return the figure a projector has to publish in ANSI or ISO lumens.
Why does the screen type change the number?
Because gain multiplies what reaches your eye. A light rejecting screen at 1.2 gain needs about a sixth less projector than plain matte white, and a screen made for ultra short throw at 0.6 gain needs two thirds more. The right screen is often cheaper than the brighter projector.
What about those 20,000 lumen projectors?
That figure is almost always in LED lumens or lux, neither of which compares to ANSI. We do not convert between them, so a projector quoting one simply shows that its brightness is not confirmed and never satisfies a requirement here.