Screen Size Calculator

Calculate TV or monitor dimensions from diagonal size and aspect ratio. Find optimal viewing distance.

By Konstantin Iakovlev · Updated April 2026 · Source: IETF

in
Aspect Ratio

Width

47.9"

Height

27.0"

Area

1,292.6 in²

Screen Dimensions

Width47.94 in (121.8 cm)
Height26.96 in (68.5 cm)
Screen Area1,292.6 in² (8,339 cm²)

Optimal Viewing Distance

Minimum (1.5× diagonal)82.5 in (6.9 ft)
Maximum (2.5× diagonal)137.5 in (11.5 ft)
Recommended Range6.9 – 11.5 ft

Use the Screen Size Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.

How It Works

Knowing a screen's diagonal alone tells you surprisingly little about how it will sit on a wall or stand. What actually matters for fit is the width and height, and those depend on both the diagonal and the aspect ratio. As the average diagonal on new TVs climbs toward 65 inches by early 2026, the gap between the number on the box and the footprint in your room keeps widening, which is exactly what this tool resolves.

The dimensions come straight out of the Pythagorean theorem. For a diagonal d and an aspect ratio w:h, width and height work out to W = d * (w / sqrt(w^2 + h^2)) and H = d * (h / sqrt(w^2 + h^2)). Viewing distance scales with the diagonal as well: roughly 1.5 to 2.5 times the diagonal suits 4K content, while 1080p generally looks best at 3 to 5 times the diagonal, far enough that individual pixels disappear.

One trap worth avoiding is treating the active display area as the full size of the set. Bezels add inches the formula never sees, so measure your available space and leave margin before you commit to a model. Bigger is not automatically better, either: a panel that overwhelms a short viewing distance trades immersion for eye strain, and one viewed from too far simply wastes resolution.

Example: Setting up a 75-inch 4K TV

  1. 1 Input a diagonal screen size of 75 inches and an aspect ratio of 16:9.
  2. 2 The calculator determines the screen's width to be approximately 65.2 inches (165.6 cm) and its height to be 36.7 inches (93.2 cm). For a 4K TV, the optimal viewing distance would be between 112.5 inches (9.4 feet) and 187.5 inches (15.6 feet).
  3. 3 The 75-inch TV has a display area of roughly 65.2 inches wide by 36.7 inches high. The ideal viewing distance is 9.4 to 15.6 feet.
  4. 4 This information is vital for selecting the correct TV stand or wall mount and for arranging your seating to achieve the best possible viewing experience for your new 4K television in 2026.

Source: IETF · Last updated: April 2026

Frequently Asked Questions

What is the best TV size for my room?
A common guideline is that viewing distance should be 1.5 to 2.5 times the diagonal screen size. For a 10-foot viewing distance, a 65 to 75 inch TV is ideal.
How do I calculate TV dimensions from diagonal size?
For a 16:9 TV, multiply the diagonal by 0.872 for width and 0.49 for height. A 65-inch TV is about 56.7 inches wide and 31.9 inches tall, not including the stand.
What does aspect ratio mean for screens?
16:9 is the standard widescreen ratio for TVs and most monitors. Ultrawide monitors use 21:9 for extra horizontal space. The aspect ratio determines the shape of the screen, not the size.