Screen Size Calculator
Calculate monitor and TV screen width, height, diagonal size and screen area from the diagonal measurement and aspect ratio.
Screen Size Results
What Is a Screen Size Calculator?
A screen size calculator helps you calculate the physical width and height of a TV, monitor, laptop or other display when you know its diagonal size and aspect ratio.
Most screens are advertised by their diagonal measurement, such as 24-inch, 27-inch, 32-inch, 43-inch, 50-inch or 55-inch. However, the diagonal measurement does not directly tell you the actual screen width and height.
This calculator uses the diagonal size and aspect ratio to calculate the actual screen dimensions. Results are provided in both inches and millimeters (mm).
How to Calculate Screen Width and Height
The diagonal, width and height of a screen form a right triangle. The Pythagorean theorem can therefore be used to calculate the physical dimensions of the display.
For an aspect ratio of W:H, the width and height can be calculated using:
Height = Diagonal × H / √(W² + H²)
The calculator automatically applies these formulas based on the diagonal size and selected aspect ratio.
Common Screen Aspect Ratios
16:9
16:9 is one of the most common widescreen aspect ratios. It is widely used for TVs, monitors, laptops, streaming content and video.
16:10
16:10 provides slightly more vertical screen space than 16:9 and is commonly found on productivity monitors and some laptops.
21:9
21:9 is commonly used for ultrawide monitors and provides a wider horizontal workspace.
32:9
32:9 is an extremely wide aspect ratio often used for super-ultrawide monitors.
4:3
4:3 was widely used by older televisions and computer monitors and is still used in some specialized displays.
Inches to Millimeters Conversion
The calculator also converts screen dimensions from inches to millimeters automatically.
Millimeters = Inches × 25.4
For example, a 50-inch 16:9 screen has an approximate width of 43.58 inches, which is about 1106.9 mm.
Screen Size Calculator for TV and Monitor
You can use this free calculator for TVs, desktop monitors, ultrawide monitors, gaming displays, laptops and other rectangular screens. Simply enter the diagonal screen size and select the correct aspect ratio.
The calculator will provide the estimated physical width, height, diagonal measurement and screen area.
Frequently Asked Questions
How do I calculate the width of a 50-inch TV?
For a 50-inch 16:9 TV, the screen width is approximately 43.58 inches or 1106.9 mm.
How many millimeters are in one inch?
One inch is exactly equal to 25.4 millimeters.
Does TV size mean width?
No. TV size normally refers to the diagonal measurement of the display, not its horizontal width.
What is the most common TV aspect ratio?
16:9 is a widely used aspect ratio for modern televisions and many computer displays.
Can I calculate a custom screen aspect ratio?
Yes. Select Custom Ratio and enter the width and height values of your desired aspect ratio.
Can this calculator calculate monitor dimensions?
Yes. You can use it for monitors, TVs, laptops, gaming displays and ultrawide screens as long as the diagonal size and aspect ratio are known.