Watching movies and playing games on a projector are great. Once you get used to the giant display, it’s much harder to watch on even the largest TVs. But before you buy a projector, you’ll need to make sure you have the space for it.

The projector itself won’t need too much leeway, but you’ll need to make sure you have enough room between it and your screen to get to your desired screen size. With a little math, it’s easy to figure out just how deep your living room needs to be.

Throwing It Out There

You’ll see a few specs and industry jargon when you start researching projectors. The main one to pay attention to is the “throw ratio,” also known as “throw distance.” You’ll use this to calculate just how far from your screen the projector needs to sit. If the throw distance is “1” then you’ll need to place the projector one foot from the screen to display a one-foot diagonal image. If the throw ratio is less than one, you can place the projector less than one foot from the screen to make a one-foot diagonal image. Following that, if the throw ratio is more than one, you’ll need to place the projector more than one foot from the screen to produce a one-foot image.

You’ll often see projectors with more than one throw ratio listed. This means that the projector has a zoom wheel, so you can change the size of the image. Having multiple throw ratios doesn’t change our math; you just have to calculate it again.

Here’s the calculation to determine how far your projector needs to from the screen:

Throw Ratio X Desired screen size (Inches or Centimeters) = Distance from screen (Inches or Centimeters)

As an example, we can look at the BenQ HT2150ST. Let’s say we wanted a screen size of 150″ and need to know how far away to place the projector. This model has a throw ratio between 0.69 and 0.83, so our math looks like this:

0.69 (throw ratio) X 150 (desired screen size) = 103.5 (distance from screen)
0.83 (throw ratio) X 150 (desired screen size) = 124.5 (distance from screen)

Another way to gauge how much space you need is to look at the marketing or model name for the projector. You’ll see projectors advertised as “short throw,” “ultra-short throw,” or maybe without any throw distinction.

What Is an Ultra-Short Throw Projector?

An ultra-short throw projector typically has a throw ratio of less than 0.4. This means ultra-short projectors have a wide-angle lens that lets them sit as close as possible to a screen. These are great for home theaters, since you don’t have to worry about mounting the projector, and you don’t have to worry about someone blocking part of the image by walking between the projector and the screen.

I currently own a ViewSonic PX800HD projector, which has a 0.23 throw ratio. This means that since I have it placed about 40 inches from my wall, I have a 175-inch screen. And it’s glorious. Here’s our calculation, broken down for this projector:

0.23 (throw ratio) X 175 (desired screen size) = 40.25 (distance from screen)

Ultra-short throw projectors are great for anyone tight on floor space, especially renters that might not be allowed to mount the projector on the ceiling. It’s also great if you want a giant portable “monitor”: I’ve used my projector for backyard movie nights, showing photos at weddings and funerals, and everything in between. I don’t have to run a long extension cord because the projector is already sitting close to a wall.

Ultra-short throw lenses are the most expensive to produce, so with other factors like resolution and brightness being equal, these projectors are the most expensive to purchase.

What is a Short Throw Projector?

A short throw projector moves a bit farther away from the screen than its ultra short throw cousin. Shorts throws usually have a throw ratio between 0.4 and 1. This mean short throw projectors typically need to sit about five to ten feet away from the screen. You can mount short throw projectors on a ceiling or sit them on a small table in the middle of a living room.

One of the more popular short throw projectors is the BenQ TH671ST. This projector features a zoom wheel and has a throw ratio between 0.69 and 0.83. To get a 150-inch image in your home theater, this projector would need to be between 103 inches (8.6 feet) and 124.5 inches (10.38 feet) from the screen. That’s not going to work in the smallest apartments, but it’s not unreasonable in most homes. Here’s our equation again:

0.69 (throw ratio) X 150 (desired screen size) = 103.5 (distance from screen)
0.83 (throw ratio) X 150 (desired screen size) = 124.5 (distance from screen)

One issue I’ve had with short throw projectors is making sure everything gets power. The projector, my Xbox, and other gadgets were on the lower portion of a coffee table sitting in the middle of my living room. I ran a power strip with a long power cable underneath my couch and to the coffee table. From there, I placed the power strip and all the power cables for my electronics inside a cable management box and tried to make everything look as tidy as possible. It kinda worked, but I’m much happier with my ultra-short throw since I don’t need to worry as much about cable management.

Short throw projectors are between ultra-short throw and standard projectors when it comes to production costs, meaning they’re also in the middle when it comes to how much you’ll pay.

What is a Standard Projector?

We’re using “Standard” as a way to differentiate these from short-throw or ultra-short-throw projectors, but you probably won’t see the word “Standard” listed in the marketing. Standard projectors have a throw ratio higher than one and therefore need the most space to produce a giant image.

The Optoma UHD60 has a throw ratio between 1.39 and 2.22, so if you want to use it to get a 150-inch image, you’ll need to place it between 208-inches (17 feet) and 333-inches (27 feet) away from your screen. That needs a deep home theater, though it may be perfectly fine in outdoor settings. Here’s our calculation broken down:

1.39 (throw ratio) X 150 (desired screen size) = 208 (distance from screen)
2.22 (throw ratio) X 150 (desired screen size) = 333 (distance from screen)

Keep in mind, though, you can’t have anything else within that 17 feet between the projector and screen unless you want to block some of the image. You can place most standard projectors on a small table, but you’d be happier if you mounted it to the ceiling or placed it on a shelf on your wall.

Standard projectors are the least expensive type of projector to produce, so they’re also the least expensive to purchase. Just keep in mind some of your savings will go towards a mount, extra long HDMI cables, and other necessities.

So Which Is Best For You?

Figuring out which type of projector to buy comes down to two factors: space and budget. The less space you have (i.e., the shorter the throw you want), the more expensive your projector will be. But you may also get more use out of a more expensive short or ultra-short throw projector since you can get a giant image from it almost everywhere.

Keep an eye on deals too: I bought my ViewSonic PX800HD for nearly half price by getting it refurbished. It was missing a power cable, but my savings on the projector more than made that worth it.

No matter how much space you have, you can get a giant screen with the right projector!

Tom Westrick Tom Westrick
Tom Westrick has been writing about technology professionally since 2014, but he started poking and prodding at electronics as a teenager. His work has been published on Android Central, iMore, and Windows Central. When he's not writing, Tom is a Tier-1 Help Desk Technician, songwriter, and guitar player.
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