Measure an Ideal Screen Size by Throw Ratio Calculator

The projection is determined by your room size, where the projector will be placed, and the distance from the projector to the projection screen/wall. To select the ideal projector for your home, you will need to measure the length and width of the room to use the maximum distance the projector can be placed from the screen to search for the specific projector model that will meet your ideal screen size needs. If the space has an irregular shape, such as an L shape or a polygon, measure the distance between the two walls as the reference for purchasing a projector. Keep in mind the best setup position is where two walls are furthest apart in the space.

There are many choices in terms of device size and projector lens design. Among all existing projectors, a  throw ratio around 1.13:1 is the most common design that has the lens in the front of the projector. These designs can require distances as short as 8.2ft to project a 100-inch screen, which is the most common throw distance setup in limited space or small apartments.

Some projectors with the short-throw lens can save more space from the projector to the wall, offering a shorter projection distance for the same 100-inche screen (100"@6.6ft). There are also models with the lens placed inside the projector body to project images upward onto a screen above and behind the projector body. These ultra-short throw models only require a distance of less than 3.3ft to project a 100-inch screen. These options make it easy to enjoy large screens, even if the room is smaller than 6.5ft².

For spaces where the projectors cannot be aligned to the center of the screen, simply select a model equipped with vertical/horizontal keystone correction or lens shift to experience the immersive thrill of a huge screen that’s available at theatres.

If the projector can be mounted on the ceiling or placed on a table aligned to the center of the screen, only the "screen size @ distance" information is needed when selecting a projector. But if the projector cannot be aligned to the center of the screen leading to screen distortion, the projector must be equipped with keystone correction or lens shift design. Some projectors offer vertical keystone correction, while others include both vertical and horizontal keystone correction. If the projector can be aligned to the center of the screen but must be tilted at an angle to fill the screen, then only vertical keystone correction is needed to project images fully and accurately. But if the projector cannot be aligned to the center of the screen due to room décor and must be placed by a wall or a corner, a model with both vertical and horizontal keystone correction is needed.

The difference between lens shift and keystone correction is that lens shift is a physical mechanism and keystone is based on digital correction. Lens shift allows the lens to move up, down, left, and right within a certain range, so the projected picture can be moved vertically or horizontally without causing keystoning (trapezoidal distortion). Regardless of where the projector will be placed, select a model equipped with lens shift or keystone correction to enjoy 100” plus cinematic experiences in your home.