Answer first
What this calculator tells you
Calculate a screen's width, height and area from its diagonal size and aspect ratio. Check whether a TV or monitor fits a stand or a wall space before you buy. Formula: Height = diagonal ÷ √(1 + a²); width = a × height, where a is the width-to-height ratio; area = width × height. At the worked-example inputs, the screen width (in) is 56.7. Holding every other input steady, moving screen diagonal (in) from 52 to 78 moves the result from 45.3 to 68.
Transparent method
The formula
Check whether a TV or monitor fits a stand or a wall space before you buy.
Worked example
Example inputs
How to interpret the result
A TV is sold by its diagonal, but a stand or a wall needs its width. A 65 inch 16:9 screen is 56.65 inches wide and 31.87 inches tall, or about 12.5 square feet of screen. The width is the number to compare with the space and the stand.
At the worked-example inputs the screen width (in) is 56.7. It rises with screen diagonal (in) and falls as aspect ratio increases.
This educational estimate omits individual tax and legal considerations.
Before you rely on it
What to check
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.
The common error
Where people go wrong with TV size calculator
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.
Sensitivity evidence
How screen diagonal (in) changes the screen width (in)
Holding every other input at the worked-example value, moving screen diagonal (in) from 52 to 78 moves the screen width (in) from 45.3 to 68: a spread of 22.7, or 40% of the worked-example result.
| 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 |
| 65worked example | 56.7 | 31.9 | 12.5 |
| 72 | 62.8 | 35.3 | 15.4 |
| 78 | 68 | 38.2 | 18.1 |
Every input, tested
Which input moves the screen width (in) most
Of the 2 inputs, screen diagonal (in) moves the screen width (in) most (11.3 across the range tested) and aspect ratio moves it least (4.7).
| Input | Tested from | To | Screen width (in) at each end | Swing |
|---|---|---|---|---|
| Screen diagonal (in) | 59 | 72 | 51.4 to 62.8 | 11.3 (20%) |
| Aspect ratio | 16:9 | 4:3 | 56.7 to 52 | 4.7 (14%) |
Step by step
The worked example, input by input
| Input | Value used | What it means |
|---|---|---|
| Screen diagonal (in) | 65 | Enter the screen diagonal (in) used in this calculation. |
| Aspect ratio | 16:9 | Most TVs are 16:9. Ultrawide monitors are often 21:9. |
| Screen width (in) | 56.7 | |
| Screen height (in) | 31.9 | |
| Screen area (sq ft) | 12.5 | |
Inputs, definitions and assumptions
Screen diagonal (in)
Enter the screen diagonal (in) used in this calculation. The prefilled worked-example value is 65.
Aspect ratio
Most TVs are 16:9. Ultrawide monitors are often 21:9. The prefilled worked-example value is 16:9.
How to use this calculator
- 1Verify the inputs. Gather screen diagonal (in) and aspect ratio from your own documents; the prefilled values are examples.
- 2Save a baseline. The worked example puts the screen width (in) at 56.7. Store your own version of it as Scenario A.
- 3Test one change. Start with screen diagonal (in), the input with the biggest effect here: moving screen diagonal (in) from 59 to 72 takes the screen width (in) from 51.4 to 62.8, a swing of 20% of the worked-example figure.
- 4Check the extremes. At half the example screen diagonal (in) (32.5) the screen width (in) is 28.3; at double (130) it is 113.3.
People also ask
Frequently asked questions
How do you calculate TV size?
Height = diagonal ÷ √(1 + a²); width = a × height, where a is the width-to-height ratio; area = width × height. At the worked-example inputs the screen width (in) is 56.7.
What does the TV size result mean?
Check whether a TV or monitor fits a stand or a wall space before you buy. At the worked-example inputs the screen width (in) is 56.7. It rises with screen diagonal (in) and falls as aspect ratio increases.
How much does screen diagonal (in) change the screen width (in)?
Holding every other input at the worked-example value, moving screen diagonal (in) from 52 to 78 moves the screen width (in) from 45.3 to 68, a spread of 22.7.
What are the limits of this TV size calculator?
This educational estimate omits individual tax and legal considerations. The tables on this page test screen diagonal (in) only from 52 to 78; a value outside that range is not tabulated here.
Which input moves the screen width (in) most in the TV size calculator?
Ranked by how far each moves the screen width (in) across the range tested: screen diagonal (in) (11.3, 20%) and aspect ratio (4.7, 14%).
If I double screen diagonal (in) in the TV size calculator, does the screen width (in) double?
Doubling it from 65 to 130 takes the screen width (in) from 56.7 to 113.3, which is 2.00 times the worked-example figure. So the result scales almost exactly in proportion. Halving it to 32.5 gives 28.3.
How much does aspect ratio matter in the TV size calculator?
The worked example uses 16:9. With the other inputs left at the worked example, switching aspect ratio changes the screen width (in): 16:9 gives 56.7; 21:9 gives 59.7; 16:10 gives 55.1; 4:3 gives 52.
Which inputs change the screen height (in) in the TV size calculator?
At the worked-example inputs it is 31.9. Screen diagonal (in) takes it from 28.9 to 35.3 and aspect ratio takes it from 31.9 to 39.
Which inputs change the screen area (sq ft) in the TV size calculator?
At the worked-example inputs it is 12.5. Screen diagonal (in) takes it from 10.3 to 15.4 and aspect ratio takes it from 12.5 to 14.1.
How do I split a bill fairly when orders differ?
Apportion each person's share of the pre-tax subtotal, then allocate tax and any tip proportionally to those shares. Splitting the total evenly is simpler and systematically overcharges whoever ordered least.
Is a percentage point the same as a percent?
No, and the distinction matters. Moving from 4% to 5% is a rise of one percentage point but a 25% increase in the rate itself. Reports that blur the two can overstate or understate a change dramatically.
Sources and evidence
Free Calculators Online is independent and is not affiliated with or endorsed by the source organizations. Educational estimates only.