TV Size Calculator

When to Use This Tool

Planning to buy a new TV but aren't sure what size fits your living room? Or wondering if a specific TV will actually fit in your entertainment center? With this calculator, simply enter the diagonal screen size in inches (e.g., 65 inches) and select the aspect ratio (commonly 16:9 or 4:3) to instantly see the screen's width, height (in centimeters), and total area. It also provides the optimal viewing distance to help you decide if it's the right fit for your space.

How It Works: Principles and Formulas

Screen sizes are typically measured by their diagonal length in inches. 1 inch = 2.54 centimeters. For a known aspect ratio (like 16:9), we can calculate the exact width and height using the Pythagorean theorem:

• Width = Diagonal × Aspect Ratio Width / √(Width² + Height²)
• Height = Width ÷ Aspect Ratio (Width/Height)

More directly: Let the aspect ratio be a:b and the diagonal be D (in inches). The width (in cm) = 2.54 × D × a / √(a² + b²)；the height (in cm) = 2.54 × D × b / √(a² + b²).
Screen Area = Width × Height (in square centimeters).
Recommended Viewing Distance: It is generally recommended to be 2.5 to 3 times the screen height (for 16:9 Full HD), or 3 to 4 times (for 4K resolution). We provide a range based on 2.5 to 3 times.

Typical Use Cases

• Buying a TV for a Living Room Remodel: After measuring the width of your TV wall, use the calculator to work backward and find the maximum TV size you can fit. For example, if the wall is 1.8 meters wide and you leave some space on both sides, the usable width is about 1.6 meters. Test different sizes in the calculator to find a model with a width under 1.6 meters.
• Choosing a Size for a Bedroom or Small Room: The viewing distance in a bedroom is usually 2 to 3 meters. Use the calculator to find the recommended viewing distances for various sizes and choose one that matches the distance from your bed or sofa to the wall.
• Upgrading from an Old 4:3 TV: Older TVs use a 4:3 aspect ratio, meaning their actual width is smaller than a 16:9 TV with the same diagonal size. By calculating both ratios, you'll see that a 65-inch 16:9 TV is significantly wider than a 65-inch 4:3 TV, helping you avoid buying a TV that won't fit your current TV stand.

Step-by-Step Example

Let's look at a specific example. Suppose you want to buy a 65-inch, 16:9 TV.
In our calculator, enter "65" for the diagonal, select "16:9" for the aspect ratio, and click calculate:

1. Diagonal in cm = 65 × 2.54 = 165.1 cm
2. For a 16:9 ratio, √(16²+9²) = √(256+81) = √337 ≈ 18.358
3. Width = 165.1 × 16 / 18.358 ≈ 143.9 cm
4. Height = 165.1 × 9 / 18.358 ≈ 80.9 cm
5. Screen Area ≈ 143.9 × 80.9 ≈ 11,642 cm² (about 1.16 m²)
6. Recommended Viewing Distance = Height × 2.5 to 3 = 2.02 m to 2.43 m

Interpreting the Results: This TV is about 1.44 meters wide and 0.81 meters high. If your TV stand is over 1.5 meters wide, it will fit perfectly. The optimal viewing distance is between 2 and 2.4 meters, which suits the sofa-to-wall distance in most living rooms.

More Examples

Comparison Example 1: 55-inch 16:9 TV
Same aspect ratio, 55-inch diagonal. The calculated width is ≈ 121.8 cm, height ≈ 68.5 cm, area ≈ 8,343 cm², and recommended viewing distance is 1.71 to 2.06 meters.
Compared to the 65-inch model, it is 22 cm narrower and has about 28% less screen area. It is ideal for bedrooms or small living rooms with a viewing distance of under 3 meters.

Comparison Example 2: 50-inch 4:3 Older TV
50-inch diagonal, 4: