How to Calculate Projector Screen Size

Determining the right size projector screen for your needs is an important part of creating an ideal home theater or presentation setup. The screen size impacts the viewing experience, placement options, required projection brightness, and more. Follow this guide to learn how to calculate the best projector screen size for your space and usage.

Step 1: Determine the Aspect Ratio

Projector screens come in different aspect ratios, with the most common options being:

  • 4:3
  • 16:9
  • 16:10

The aspect ratio refers to the proportional relationship between the screen’s width and height.

Most modern projectors use a 16:9 widescreen aspect ratio, which is the same as an HDTV. However, older projectors may use 4:3. Selecting the aspect ratio depends on:

  • The projector’s native resolution
  • The content you’ll display (i.e. movies are usually 16:9)
  • Personal preference

Step 2: Measure the Room

Once you’ve selected the aspect ratio, measure the room to find the maximum screen size that will fit. Consider:

Distance from the Seating to Screen

The ideal viewing angle for a projector screen is 30-40 degrees. To achieve this, the seating should be 1-1.5 times the screen width away.

Use a tape measure to determine the distance between potential seating locations and the screen position. This will give you a maximum width to work within.

Open Wall Space

Measure the height and width of the open wall space intended for the screen. This gives you the maximum physical space available.

Tip: Remember to account for potential borders, frames, or surround sound speakers that may also occupy wall space.

Projector Throw Distance

The projector’s throw ratio determines how far back it needs to be positioned from the screen to project a given image size. Consult the specs to ensure your screen size works with the projector’s throw distance range.

Step 3: Calculate the Maximum Screen Size

With these measurements, you can determine the ideal screen size using some simple calculations:

By Viewing Angle

  • Take the seating distance and multiply it by 0.8-1.3x depending on desired angle.
  • This number is the maximum recommended width.
  • Divide by the aspect ratio to get height.
  • For example, if sitting 12 ft back and using a 16:9 screen:
  • 12 ft x 1.1 = 13.2 ft wide x 9 ft tall

By Wall Space

  • Take the wall height and multiply by the aspect ratio to get width.
  • Take the wall width and divide by the aspect ratio to get height.
  • Use the smaller of the two dimensions.

Example for a 16:9 screen with a 12 ft wide x 8 ft high space:

  • 8 ft high x 16/9 = 14.2 ft wide (too big)
  • 12 ft wide / 16/9 = 6.75 ft high (uses full width)
  • Therefore, maximum is 12 ft wide x 6.75 ft high

Use the smaller calculated size from the viewing angle and wall space. This gives you the largest screen size possible for the room.

Step 4: Select the Screen Size

Once you’ve calculated the maximum screen size, you can select the actual size to use based on:

Seating Layout

Ideally, all seating locations should fall within the ideal 40 degree viewing angle. Evaluate different size options to find the best fit.

Projector Brightness

Bigger screens require brighter projectors. Make sure to pick a size that matches the brightness of your projector.


Larger screens cost more. Find a size that fits your budget constraints.

Immersion Preference

Bigger screens create a more immersive cinematic experience. Balance size with other factors for the right feel.

Step 5: Find Available Screen Sizes

The Projector screens come in specific sizes. Once you’ve determined the maximum size, look for an available screen in that range.

Tip: Size up for a more immersive experience or size down if concerned about brightness.

Some common 16:9 screen sizes and dimensions include:

  • 100 inch diagonal – 87 x 49 inches
  • 120 inch diagonal – 104 x 58 inches
  • 150 inch diagonal – 130 x 73 inches

Use a projector screen size calculator to see dimensions for different sizes.

Step 6: Calculate Screen Resolution

One final calculation is to make sure your projector’s native resolution matches the screen resolution.

To determine the screen resolution:

  • Take the screen width in inches and multiply by the pixel width of the projector’s resolution.
  • Take the screen height in inches and multiply by the pixel height.

For example, a 1920 x 1080 projector with a 130 inch 16:9 screen:

  • 130 x 1080 = 140,400 pixels wide
  • 73 x 1920 = 140,160 pixels high

This aligns correctly, indicating it can display full HD resolution on the screen.

Following these key steps will help you identify the perfect projector screen size for your space and setup. Carefully calculating the maximum size, finding an available match, and verifying resolution will result in the ideal viewing experience.