What this calculator does
The Projector Calculator estimates the screen size you will get from a projector at a given throw distance and throw ratio, so you can plan a home theater or presentation room setup.
How the calculation works
A projector’s throw ratio is defined as throw distance divided by image width, so image width is calculated as throw distance ÷ throw ratio. Screen height is then derived from the width using the selected aspect ratio (for example, a 16:9 screen has a height equal to 9/16 of its width). The diagonal size, the number usually quoted for screens and TVs, is found with the Pythagorean theorem: the square root of width squared plus height squared.
This is a general planning estimate for typical fixed-lens or fixed-ratio projectors. Projectors with zoom lenses support a range of throw ratios, so check your specific projector’s minimum and maximum throw ratio for a more precise setup.