For video projectors this ratio is the throw distance divided by the width of the projected image. A fixed throw projector can only change the image size by moving the projector closer or farther from the screen. Video projectors with a zoom feature can adjust the image size by zooming in or out, while leaving the projector itself unmoved.

Ratio of projection distance to projection surface width. Throw ratio is determined using the following calculation: Throw Ratio = Projection distance / Projection surface (screen) width. These are often utilized to design fixed installations.

The ratio between the projection distance and image width in m. A throw ratio of 1,3 - 1,8:1 means, i.e., the lens of the projector achieves an image width of 1 m at a projection distance of 1,3 and 1,8 m..