TV Size Calculator
Find a screen's width and height from its diagonal.
TVs are sold by diagonal — find the actual width and height.
How the Math Works
The TV Size Calculator uses the Pythagorean theorem to determine screen dimensions from the diagonal measurement and aspect ratio. Since a TV screen forms a rectangle, the diagonal, width, and height create a right triangle. The formula states that width squared plus height squared equals diagonal squared (a² + b² = c²). Given the diagonal and the proportional relationship between width and height (the aspect ratio), we can solve for both dimensions simultaneously.
Practical Applications
To use this calculator, first determine your TV's diagonal size in inches and identify its aspect ratio (commonly 16:9 for modern HDTVs). Input these values into the calculator, which then applies the Pythagorean theorem to compute the exact width and height measurements. This is particularly useful when measuring mounting spaces, selecting TV stands or wall mounts, or ensuring your TV fits within a specific entertainment center enclosure.
Day-to-Day Use
Knowing your TV's exact dimensions helps you avoid costly mistakes when purchasing furniture or mounting equipment. Whether you're moving, redecorating your living room, or setting up a home theater, this calculation ensures your new TV will actually fit where you plan to place it. It's also valuable when comparing different TV sizes to understand how much physical space each model will occupy in your home.
Worked example
55" 16:9 → 47.9" × 27.0".
FAQ
Wall fit?
Use the width and height (not the diagonal) for clearance.