How Is a TV Measured to Determine Screen Size

Imagine if you spent months searching for a quality TV for your home entertainment room. You finally purchase the television you want at a price you can afford. When it is installed, you are disappointed. It seems to be out of place in the room. This may happen because you did not know how screen size correlates to actual TV size.

How Is a TV Measured to Determine Screen Size

There is a process to measure the screen size of a TV. Read on to find out more about how TVs are measured so that you can pick the proper size for a space.

How to Measure a TV Screen?

Balance is essential when you consider placing a TV in a room. Don’t be tempted to buy the biggest television if the room is small. Likewise, it is not a good idea to save money by getting a tiny TV for a large room. The primary TV size guidelines for common media rooms are:

  • 60 to 90 inches for home theaters
  • 50 to 64 inches for large living rooms or family rooms
  • 33 to 49 inches for medium living rooms or larger bedrooms
  • 32 inches or smaller for average bedrooms
  • 32 inches or smaller in kitchens, dorms, and small apartments

Although these are suggested guidelines, the final choice for your screen size is entirely up to you. If you enjoy watching movies on “larger-than-life” sized screens, don’t hesitate to buy the biggest television you can afford. What’s important is that you know how to measure a TV screen correctly before you purchase the TV to fit the room correctly.

There are three key factors you need to know about taking TV screen measurements. They are:

  • The viewable screen size
  • The frame dimensions or bezel
  • The size of the space where the TV will be placed

All screen sizes are stated in inches. The numbers represent the diagonal measurement from the top left to the bottom right corner. You should measure the screen diagonally to get the correct size. TV screens were originally measured diagonally because:

  • They had round picture tubes which projected screen images.
  • The screen could not be larger than the circular tube.
  • Measuring the tube provided the measurement of the screen.

Expressing the size of a television screen this way remains a standardized practice. However, not all of the advertised screen size is “viewable” since a small part of the screen is covered by a frame or bezel. However, store advertisements include the bezel in the diagonal television screen size measurements.

The part of the screen where you actually see the picture is slightly smaller. Television screen frames are usually between ½ to 3 inches wide, but frame widths vary with each television manufacturer. This creates variances between total screen size and viewable screen size. Below are examples of some advertised diagonal screens versus their actual screen sizes.

  • Advertised 40 inches, actual size 39.9 inches
  • Advertised 55 inches, actual size 54.6 inches
  • Advertised 65 inches, actual size 64.5 inches
  • Advertised 75 inches, actual size 74.5 inches

You may have seen the word “class” in a TV ad. For example, an ad might list a 70-inch “class TV.” This term is used because the frame needs to cover a small panel part to secure it. Stores use the word “class” to combat claims of false advertising.

If you plan to buy a TV, here’s how to measure the screen:

  • Install a measuring app on your mobile device. They are available on Android and iOS.
  • The television you want to buy might be on display in the store. Use a measuring tape and place it diagonally across the screen within the bezel.
  • Carefully read the manufacturer’s product specifications, usually found on the outside of the box.
  • Search for the brand, make, and model of the TV online. The specs will be on the manufacturer or retailer website.

When shopping for a television, it’s a good idea to keep a tape measure with you so that you can measure the total height, depth, and width of the TVs too. These measurements can help you determine if the television will fit in the space you intend to place it.

Buying a new TV isn’t the only reason why you may need to measure it.

Maybe you need to know how to measure the screen on a TV you already own to sell it, or you intend to move it to another location in your home. You can calculate your TV screen several ways, like:

  • Install the latest measuring app on your mobile device.
  • Check your owner’s manual for screen measurements.
  • Search online for the brand, make, and model to get the specifications.
  • Measure by securing a tape measure diagonally across the screen.

You can also use everyday items found in your home if you don’t have a tape measure. Try these items in a pinch:

  • Tape sheets of standard 11” printer paper diagonally across the screen to calculate the measurement.
  • A dollar bill is exactly 6 inches long. Use paper currency to measure the screen diagonally.
  • Use a ruler to measure the screen. Be sure to protect the screen from scratches.
  • Place a string or rope across the screen diagonally and mark off the distance between the bezel. Use another pre-measured household item to measure the string.

Don’t take a chance on having to uninstall and move a wall-mounted TV. Learn how to take measurements of your screen in certain areas to mount it correctly the first time. Wall-mounted TVs must be placed at the correct eye level for optimal viewing comfort.

For example, most movie action happens at the center third of the screen. To ensure you don’t miss out on the action, measure your television, so your eyes are level with this area when you’re in a sitting position. Check out these tips before you mount your TV:

  • Measure the height of your screen so you know where the middle of the screen is located.
  • Measure the width of your screen to ensure you purchase the correct wall mount.
  • Measure the viewable screen size to choose the best location in the room to mount it.

Measuring a projector TV screen is a unique process. The screen’s aspect ratio can depend on the purpose of the display. Common projection screen ratios include:

  • 4:3 for general settings like watching movies
  • 4:3 for classrooms or boardrooms
  • 16:9 to view in HD
  • 16:10 to view in widescreen

You may already own a projection TV for home entertainment. Here’s how to measure a projector TV screen if you plan to replace it:

  1. Measure the screen length from the top left to the bottom right corner (like a regular TV screen).
  2. Turn your aspect ratio into a fraction (for example, 6:19 would be 16/9).
  3. Measure the width of the screen.
  4. Multiply it by the fraction to get the height.
  5. Add height2 plus width2. This equals the diagonal2.

The square root of this number is the diagonal measurement of your projector TV screen, based on the Pythagorean Theorem (a2+b2=c2).

Home Entertainment in Size “You”

Your home entertainment space is a relaxing environment, and the TV is the central feature. There is no hard rule about the screen size; it is your personal choice. However, some general guidelines can help you ensure the perfect fit.

Do you watch television? Let us know how often you watch TV. Include the size of your largest television. Use the comment box below for your response.

Disclaimer: Some pages on this site may include an affiliate link. This does not effect our editorial in any way.