Projector Throw Distance Calculator

This calculator gives the lens-to-screen distance for mounting a projector at a chosen image size. It multiplies the lens throw ratio by the image width (distance = throw ratio times image width), deriving the width from the image diagonal and aspect ratio. Enter the throw ratio from the lens spec, the image diagonal, and the aspect ratio to get the mounting distance plus the resulting image width and height. Switch the mode to solve the other way: if you do not know the lens yet but you know how far back the projector sits and the screen size, enter those to get the throw ratio you need. Results read in feet and inches or meters and centimeters from the unit toggle.