TV size calculator
Pick how far the sofa is from the wall and this calculator suggests a TV diagonal, or enter a TV size to see how far to sit. It uses a viewing-angle guide: the screen fills a chosen share of your horizontal view.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Choose what you know: the distance from your seat, or the TV size.
- Pick a viewing angle and the screen shape.
- Read the matching diagonal or distance, plus the screen width and height.
How it works
For a screen of width w to fill an angle θ at distance d: w = 2 × d × tan(θ ÷ 2). The width of a 16:9 TV is its diagonal × 0.8716, and a 21:9 screen is its diagonal × 0.9191.
Worked example
A 55 inch 16:9 TV is 47.9 inches wide. For a 40° angle: distance = 47.9 ÷ (2 × tan 20°) = 65.9 inches, about 5.5 feet or 1.67 m. With a 30° angle the same TV suits about 7.5 feet.
Tips
- Measure the distance to the screen, not to the wall behind the stand.
- Sitting further away than the result is fine: the picture simply fills less of your view.
- The calculator gives screen size only. Check the width of the whole TV including its frame before buying.
Frequently asked questions
What size TV should I buy for my room?
Measure the distance from where you sit to the screen, enter it and read the diagonal. Then round to the nearest size on sale, which are usually 43, 50, 55, 65, 75 or 85 inches. Check also that the TV fits the wall or stand.
What do the 30° and 40° angles mean?
They are the horizontal angle the screen covers in your view. About 30° is a common guide for a comfortable, cinema-like picture and 40° is more immersive. They are rules of thumb, not a standard you must follow.
How is the distance calculated?
Screen width = diagonal × 16 ÷ √(16² + 9²) for a 16:9 TV. Distance = width ÷ (2 × tan(angle ÷ 2)). The calculator solves this in either direction.
Does resolution change the right distance?
This calculator ignores it. Sharper screens such as 4K let some people sit closer without seeing pixels, but the angle guide is about comfort and immersion, so it stays the same.