Screen Size Calculator
Enter a screen size such as 55 inches and an aspect ratio to get the width and height. You can also start from a width or height to find the diagonal. A drawing beside a 5 ft 7 in person helps you picture the size.
Size preview
What the size in inches means
The size of a TV, monitor or screen in inches is the length of the picture's diagonal. One inch is defined as 25.4 mm. A "55-inch" TV has a picture area whose diagonal is 55 inches.
The diagonal is measured across the area where the picture appears and does not include the outer frame (bezel). The outer size of the product, with its frame, is larger than the result here. How a size is quoted can differ between products and screens, so check the maker's specifications.
How to read the size preview
The drawing under the result shows the front of the screen at the same scale as a person who is 170 cm (about 5 ft 7 in) tall. The shape of the screen and its size relative to the person follow the width and height calculated above; only the overall scale changes to fit the drawing.
- The person is only a reference for comparing size and is not part of the calculation.
- The screen and the person are drawn with their feet on the floor. The drawing does not show the real mounting height (a wall-mounted screen is usually higher than the floor).
- Dimensions in the drawing are in inches. They are rounded the same way as in the result, while the shapes are drawn from the unrounded values.
How it is calculated
For an aspect ratio of a:b, the width, height and diagonal are linked by the Pythagorean theorem.
- Width = diagonal × a ÷ √(a² + b²)
- Height = diagonal × b ÷ √(a² + b²)
- Diagonal = √(width² + height²)
Square roots are calculated to 12 decimal places.
Examples
| Diagonal | Aspect ratio | Width × height |
|---|---|---|
| 55 in | 16:9 | about 47.94 × 26.96 in (121.76 × 68.49 cm) |
| 65 in | 16:9 | about 56.65 × 31.87 in (143.9 × 80.94 cm) |
| 100 in | 16:9 | about 87.16 × 49.03 in (221.38 × 124.53 cm) |
| 27 in | 16:10 | about 22.9 × 14.31 in (58.16 × 36.35 cm) |
| 32 in | 4:3 | about 25.6 × 19.2 in (65.02 × 48.77 cm) |
Going the other way, a 16:9 screen that is 1,920 mm wide is 1,080 mm high, with a diagonal of about 2,202.9 mm (about 86.73 in).
Notes
- Choose the aspect ratio from 16:9, 16:10, 4:3, 3:2, 21:9, 1:1 and 5:4, or choose "Other" and enter the numbers (a decimal ratio such as 2.39:1 works too). The ratio is always width : height.
- Lengths can be entered in inches, cm, mm, m or feet (1 ft = 0.3048 m), with decimals (up to 12 digits before the point and 6 after). Use a period as the decimal separator; commas are accepted only as thousands separators.
- Results are rounded to 1 decimal place for millimeters and 2 for centimeters and inches.
- On real products, the picture's aspect ratio and visible area can differ slightly from the stated values.
- To find an aspect ratio from pixel dimensions, use the Aspect Ratio Calculator. For where to place a projector, see the Projector Throw Distance Calculator.
Frequently asked questions
How wide is a 55-inch TV?
About 47.94 in (121.76 cm) wide and 26.96 in (68.49 cm) high for a 16:9 screen. That is the picture area; the frame adds to the outside size.
Is the screen size measured with or without the bezel?
Without. The diagonal is measured across the picture area only.
Can I find the diagonal from a width?
Yes. Choose "Diagonal from a width or height", enter the width and the aspect ratio, and the tool gives the height and the diagonal.