TV Size: worked example
| Screen diagonal (in) | 65 |
|---|---|
| Aspect ratio | 16:9 |
| Screen width (in) | 56.7 |
| Screen height (in) | 31.9 |
| Screen area (sq ft) | 12.5 |
Screen diagonal is the advertised size in inches, measured from one corner to the opposite corner. The aspect ratio is the width divided by the height: 16:9, which is 1.778, for most TVs and monitors, and about 2.39 for ultrawide screens. The tool computes the width, height and area from these two values.
Measure your space, including the stand and any furniture, before shopping.
TV Size: formula
TV Size: changing Screen diagonal (in)
| Screen diagonal (in) | Screen width (in) | Screen height (in) | Screen area (sq ft) |
|---|---|---|---|
| 52 | 45.3 | 25.5 | 8 |
| 59 | 51.4 | 28.9 | 10.3 |
| 65 (example) | 56.7 | 31.9 | 12.5 |
| 72 | 62.8 | 35.3 | 15.4 |
| 78 | 68 | 38.2 | 18.1 |
TV Size: compare input ranges
| Input | Tested from | To | Screen width (in): low input | Screen width (in): high input | Swing |
|---|---|---|---|---|---|
| Screen diagonal (in) | 59 | 72 | 51.4 | 62.8 | 11.3 (20%) |
| Aspect ratio | 16:9 | 4:3 | 56.7 | 52 | 4.7 (14%) |
TV Size: individual input comparisons
| Input | Value | Screen width (in) | Screen height (in) | Screen area (sq ft) |
|---|---|---|---|---|
| Screen diagonal (in) | 52 | 45.3 | 25.5 | 8 |
| 59 | 51.4 | 28.9 | 10.3 | |
| 65 | 56.7 | 31.9 | 12.5 | |
| 72 | 62.8 | 35.3 | 15.4 | |
| 78 | 68 | 38.2 | 18.1 | |
| Aspect ratio | 16:9 | 56.7 | 31.9 | 12.5 |
| 21:9 | 59.7 | 25.6 | 10.6 | |
| 16:10 | 55.1 | 34.4 | 13.2 | |
| 4:3 | 52 | 39 | 14.1 |
TV Size: which assumptions move the result?
TV Size: values and definitions
| Quantity and definition | Value used |
|---|---|
| Screen diagonal (in) | 65 |
| Aspect ratio — Most TVs are 16:9. Ultrawide monitors are often 21:9. | 16:9 |
| Screen width (in) | 56.7 |
| Screen height (in) | 31.9 |
| Screen area (sq ft) | 12.5 |
TV Size: half and double Screen diagonal (in)
| Screen diagonal (in) | Screen width (in) |
|---|---|
| 32.5 | 28.3 |
| 65 | 56.7 |
| 130 | 113.3 |
Common error: Comparing sizes across aspect ratios. A 34 inch ultrawide monitor is much wider but no taller than a 27 inch 16:9, so the diagonal tells you little across shapes.
Bezels and stands add to the outer dimensions, so the TV's overall width is a bit larger than the screen. Curved or non-16:9 screens follow different ratios. The advertised diagonal may be rounded.
Best size also depends on resolution and room lighting, not only geometry.
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A TV is sold by its diagonal, but a stand or a wall needs its width. At a hypothetical 4:3 aspect ratio, a 65-inch diagonal gives a 52-inch screen width and a 39-inch screen height. That rectangle differs from the 16:9 example even though both diagonals are 65 inches.
These are active-screen dimensions; the cabinet, bezel and support feet have their own manufacturer-specified dimensions.
Add the bezel and the stand. The screen is a little smaller than the whole set, and many stands are wider than the screen, so check both dimensions on the spec sheet.
Convert dimensions with the unit-conversion pages, and see area calculations on the rectangle area calculator in the geometry category. The Pythagorean theorem page explains the diagonal math. Viewing distance rules of thumb, such as 1.2 to 1.6 times the diagonal for 4K, help pick a size.
What viewing distance works for a 65-inch TV?
Compare the computed screen width and height with the installation space. Viewing distance is a separate preference and display-resolution question; this diagonal conversion does not prescribe it.
How do I find the width and height from the diagonal?
For a 16:9 screen, the width is about 87% and the height about 49% of the diagonal, and the calculator computes them from the aspect ratio.
Does a bigger TV give proportionally more screen?
No. Screen area grows with the square of the diagonal, so 65 inches has about 40% more area than 55 inches.