Calculate Screen Size

Screen Size Calculator

function calculateScreenDimensions() { var diagonalSize = parseFloat(document.getElementById('diagonalSize').value); var aspectRatioWidth = parseFloat(document.getElementById('aspectRatioWidth').value); var aspectRatioHeight = parseFloat(document.getElementById('aspectRatioHeight').value); var resultDiv = document.getElementById('result'); if (isNaN(diagonalSize) || isNaN(aspectRatioWidth) || isNaN(aspectRatioHeight) || diagonalSize <= 0 || aspectRatioWidth <= 0 || aspectRatioHeight W = H * (AR_w/AR_h) // Substitute W: (H * AR_w/AR_h)^2 + H^2 = D^2 // H^2 * (AR_w^2/AR_h^2 + 1) = D^2 // H^2 * ((AR_w^2 + AR_h^2) / AR_h^2) = D^2 // H^2 = D^2 * (AR_h^2 / (AR_w^2 + AR_h^2)) // H = D * AR_h / sqrt(AR_w^2 + AR_h^2) var denominator = Math.sqrt(Math.pow(aspectRatioWidth, 2) + Math.pow(aspectRatioHeight, 2)); var screenHeight = (diagonalSize * aspectRatioHeight) / denominator; var screenWidth = (diagonalSize * aspectRatioWidth) / denominator; resultDiv.innerHTML = 'Calculated Screen Width: ' + screenWidth.toFixed(2) + ' inches' + 'Calculated Screen Height: ' + screenHeight.toFixed(2) + ' inches'; }

Understanding Screen Size and Aspect Ratio

When you buy a new TV, monitor, or even a smartphone, one of the first specifications you look at is its screen size. This is almost always given as a diagonal measurement in inches. However, the diagonal measurement alone doesn't tell you the actual physical width and height of the screen. For that, you also need to know the screen's aspect ratio.

What is Aspect Ratio?

The aspect ratio describes the proportional relationship between the width and the height of a screen. It's typically expressed as two numbers separated by a colon (e.g., 16:9, 4:3). For example:

• 16:9: This is the most common aspect ratio for modern televisions, computer monitors, and widescreen content. It means that for every 16 units of width, there are 9 units of height.
• 4:3: This was the standard aspect ratio for older, traditional televisions and computer monitors.
• 21:9 (Ultrawide): Increasingly popular for gaming monitors and some cinematic content, offering a much wider field of view.

Why Calculate Screen Dimensions?

Knowing the exact width and height of a screen is crucial for several reasons:

• Furniture Placement: Before buying a TV, you need to ensure it will fit into your entertainment center or on your wall mount.
• Viewing Distance: Understanding the physical size helps determine the optimal viewing distance for a comfortable and immersive experience.
• Content Scaling: Different aspect ratios affect how content is displayed. A 4:3 video on a 16:9 screen will have black bars on the sides (pillarboxing), while a 16:9 video on a 4:3 screen will have black bars on the top and bottom (letterboxing).
• Workspace Planning: For multi-monitor setups, knowing precise dimensions helps in arranging screens effectively.

How the Calculator Works

This calculator uses the Pythagorean theorem, a fundamental principle in geometry, to determine the screen's width and height. The diagonal measurement, along with the width and height, forms a right-angled triangle. The aspect ratio provides the proportional relationship between the width and height.

Given the diagonal (D), aspect ratio width (AR_w), and aspect ratio height (AR_h), the formulas are:

Screen Height (H) = D × AR_h / √(AR_w² + AR_h²)
Screen Width (W) = D × AR_w / √(AR_w² + AR_h²)

Simply input your screen's diagonal size in inches and its aspect ratio (e.g., 16 and 9 for 16:9), and the calculator will instantly provide you with the precise width and height of your screen.

Example Calculation:

Let's say you have a 55-inch TV with a standard 16:9 aspect ratio:

• Diagonal Size (D): 55 inches
• Aspect Ratio Width (AR_w): 16
• Aspect Ratio Height (AR_h): 9

Using the formulas:

Denominator = √(16² + 9²) = √(256 + 81) = √337 ≈ 18.3576

Screen Height (H) = 55 × 9 / 18.3576 ≈ 26.96 inches

Screen Width (W) = 55 × 16 / 18.3576 ≈ 47.93 inches

So, a 55-inch 16:9 TV is approximately 47.93 inches wide and 26.96 inches high.