When buying an LCD TV, selecting the greatest screen size is usually simple. Unless you live in a closet, you should just choose the largest screen that will fit on your wall. However, with an outdoor projection screen, you are not restricted by the wall space available. However, you are still constrained by overall space.  If you’re projecting in 1080p, your ideal viewing distance will be around 12 times the screen’s diagonal measurement. So if you have a 10-foot screen, you’ll get the optimum viewing quality from a distance of 15 feet. There’s a lot of wiggle room here, and the screen will certainly be “viewable” from any distance. The ideal distance, though, should be in the center of your audience. Don’t get a 16-foot projector if you don’t want the middle of your crowd to be 24 feet away from the screen.  If you want to make it easier to figure out your optimal screen size, there is an online calculator that can assist you. There are other more advanced brightness calculating tools in the calculator, but those are outside the scope of this essay.