Calculating Projector Screen Dimensions for 16:9 Projectors

Here are your basic formulas for calculating projector screen dimensions. They are slightly rounded for your convenience.

All calculations are based on the screen area, and do not include the borders or frame.
These calculations are for standard 16:9 aspect ratio screens (HDTV shape), which are used by the vast majority of home theater users, as the vast marjority of home theater projectors are 16:9 native aspect ratio.

Simply put, a 16:9 projection screen is 1.78 times as wide as it is high. 16 / 9 = 1.78 (rounded)

If you know your projector screen’s diagonal size:

Projector Screen Height: To calculate the projector screen height, multiply the diagonal by approximately 0.495. (In other words the height of the screen is just a bit less than 50% of the diagonal.

Projector Screen Width: The width of the projector screen is approximately 87% of the projector screen’s diagonal, so multiply the diagonal measurement by approximately 0.87.

Diagonal Size of a home theater projector screen: 100″

Projector screen height: 0.495 x 100″ = 49.5 inches
Projector screen width: 0.87 x 100″ = 87 inches

Diagonal Size of a home theater projection screen: 110″

Projector screen height: 0.495 x 110″ = 54.5″
Projector screen width: 0.87 x 110″ = 95.7″

If you know projection screen width, and need to calculate diagonal size and height of the screen:

Projector screen diagonal: To calculate the projector screen diagonal from the known width, divide the width by 0.87
Projector screen height: To calculate the projection screen height, from the known width, multiply the width by 0.57


Width of a home theater projector screen: 100″

Projector screen diagonal: 100″ / 0.87 = 115″
Projector screen height: 100″ * 0.57 = 57″

Width of a home theater projection screen: 80″

Projector screen diagonal: 80 ” / 0.87 = 92 ”
Projector screen height: 80 ” * 0.57 = 45.6 ”

It’s that easy.

News and Comments

  • Peter Swiggs

    you have your maths wrong as a 16:9 image has a height higher than half the width 0.495 is less than half. 16/2=8 not higher than 9


      Peter, I’m looking at your two posts. I’m not sure what you are saying is wrong. You say:

      16:9 image has a height higher than half the width 0.495 is less than half.

      But what I said is 0.495 is height compared to diagonal, NOT compared to width.

      As you can see for height compared to width, I’m using 0.57, which (as you point out) is larger than 50%

      As to your image of a monitor, It looks like you are using numbers that include the case, not just the display. That would distort your square root numbers, but there’s also a separate issue. Many monitors/HDTVs have display areas that are not 16:9, in ratio, only close. They simply use only the 16:9 (or in the case of commercial monitors – 16:10. We own a Sony LCDTV that has a surface area of the display that’s larger than the used area. Only slightly of course, but that isn’t uncommon.

      So, even if those measurements on your monitor image are correct in that they represent only the screen, not the bezel, that still typically does not mean that the actual LCD display is a true 16:9 (or 16:10), only that it only uses the 16:9 or 16:10 and the rest stays blank.

      For example, this right off one of the screen manufacturer’s pages:
      100” diagonal Viewing Surface Dimensions 87.2 inches wide by 49.0 inches high
      seems everyone rounds… Using their numbers and the Theorem, squaring both and adding them, you get 10,004, which is a tiny fraction over 100” (100×100 = 10,000).

      Now, if I am overlooking something in my article, a typo or such, please do point it out. But on rescanning it, it looks right to me. -art

  • Peter Swiggs

    This shows that the maths is wrong via pythagoras’s thereom:
    37.2 squared = 1383.84
    22.1 squared = 488.41
    together they = 1872.25
    the square root of that = 43.27 to 2dp the diagonal of tv n casing
    43.27 * 0.495 = 21.42 to 2dp not 22.1
    2dp equals 2 decimal places.
    images is at:

  • Ууганбаяр Амгалан

    which projector is convenient for 200 inch screen?


      In a fully darkened room, with medium to dark walls, ceiling, floor (that is, basically a home theater, then any projector with 2000 lumens, will fill a screen that size at the brightness levels found in a typical movie theater. After that, it’s about a whole lot of different levels of performance and capability.

      Technically there are business projectors from $379 on up that are bright enough, so it depends on what standards you want for picture quality, black level performance, etc., and what you are watching – business presentations, sports, movies, HDTV. -art

      • Ууганбаяр Амгалан

        Under project budget 1500$, I am planning to make home cinema/screen size 150-200/, (projector quality HD 1920×1080, 16:9, ) usually watch movie, HD, DVD, Blu-ray movie


          Hi, For 150” or larger you are going to need something bright. You won’t find anything with great black levels at that price, however. I would recommend the Optoma HD50 which is also sold as the HD161X. That’s about $1300 here. I’m currently reviewing the new BenQ HC4050, also nice but the Optoma will have better blacks. If you are rainbow sensitive look to the BenQ HC1200 of the DLP projectors, or stick with 3LCD. Best 3LCD choices at your price – refurbished 5030UB or 5020UB. (my top choice), or a Panasonic PT-AE8000U (if you can find one at your price point). -art

          • Ууганбаяр Амгалан

            Thank you, in that size how is epson 2030 or 3020 ub or benq w1070


            Between the 2030, 5020UB (discontinued but still available some places as a refurb), and W1070, my strong preference is for the Epson 5020UB refurbished. After that, I lean toward the W1070, although it’s not as bright as the 2030, when it comes to filling a large screen. -art

  • atrack

    I have a 90 inch screen and bought a 130″ projector 800*480, Contrast:800:1, Aspect Ratio: 4:3/16:9. Will I be OK to use it on that screen?


      atrack – not enough info, and confusing, don’t know how to answer – projectors don’t have sizes (130”), so I’m assuming the manufacturer says it’s good up to 130”. You didn’t mention the aspect ratio of your screen, nor what thee true aspect ratio is of the projector.

      And you didn’t indicate how bright the projector is. Since it is very low resolution, I’m guessing it’s a very small (under 2 pound) LED projector. Ultimately, if the projector is bright enough, any screen will work, but if the projector is native 4:3 then a 4:3 screen is best, if 16:9, then definitely a 16:9 screen is preferred. -art

  • Frederik Kristensen

    I need a projector that can project onto a 80″ screen with a 16:9 ratio. The throw distance is 4 meters.
    Room has white walls though it’s almost completely dark. Any suggestions?

  • Vic B

    Hello, we’re setting up a classroom where the furthest distance from the screen is 40 ft and the closest is 12 ft (17 ft max diagonal). If I’m correct, I should be looking for a 120″ dia. projector screen, right? We’re showing computer based videos of very average quality so we aren’t too concerned with image quality. We have no issues with light but possibly with heat because the projector is on 6-8 hours at a time, 2-3 times per week. Any suggestions for a projector, up to $2500? Thanks!