Projector Throw Distance Calculator

How Projector Throw Distance Works

Throw distance is the space between the projector lens and the screen. Every projector has a "throw ratio" — the ratio of throw distance to screen width. A projector with a 2.0 throw ratio needs to be placed 10 feet away to create a 5-foot-wide image. Understanding this relationship is critical for planning any projector installation.

Ultra Short Throw vs. Standard Projectors

Standard throw projectors (ratio 1.0–3.0) are the most versatile, with the widest selection and best image quality per dollar. They require 8–20+ feet of space and typically ceiling-mount. Short throw projectors (ratio 0.4–1.0) work in tighter spaces at 3–8 feet. Ultra-short throw (UST) projectors sit inches from the wall, perfect for living rooms where ceiling mounting isn't practical.

Brightness Matters: Foot-Lamberts Explained

A projector's rated lumens don't tell the whole story. What matters is foot-lamberts (fL) — the actual brightness at the screen surface. This depends on lumens, screen size, and screen gain. The SMPTE standard recommends 14–16 fL for a dark theater. Rooms with ambient light need 25–65 fL. Our calculator factors in screen gain and ambient light to tell you if your setup will look great.

For the best results, pair your projector with proper audio using our Amplifier Power Calculator, and use our Screen Size Calculator to get exact dimensions for your chosen aspect ratio.