Projector Screen Gain Calculator

How to use it: enter screen size, delivered projector lumens and a brightness target. The tool reverse-solves nominal gain and compares the same setup at 0.8, 1.0 and 1.3 gain.

Formula. Gain required = target foot-lamberts x screen area / delivered lumens. Foot-lamberts = lumens x gain / area.

Example. Doubling nominal gain doubles the ideal on-axis foot-lambert estimate, although real screens trade brightness against viewing distribution.

The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.

Screen diagonal

120 in

Aspect width

16

Aspect height

9

Delivered lumens

1600

Target brightness

16 fL

Current screen gain

1

Primary result: Required nominal gain: 0.43.

• Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
• Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
• When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.

Gain is directional and manufacturer measurements are not perfectly interchangeable. Higher gain can narrow viewing angle, create hot spots or alter color. This arithmetic does not model room reflections, ambient light rejection or screen texture; evaluate samples in the real room.