Screen Size Calculator Widget

Show readers what a screen size really means. From the advertised diagonal and the aspect ratio, the widget gives the visible width, height and area in inches or centimetres, and compares two screens - for example a 27-inch 16:9 monitor with a 34-inch ultrawide.

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<iframe src="https://a2z.tools/embed/w/screen-size-calculator" title="Screen Size Calculator by A2Z Tools" width="100%" height="800" style="border:0;width:100%" loading="lazy" allow="clipboard-write"></iframe>

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How it works

A screen's diagonal is the hypotenuse of a right triangle whose sides are in the aspect ratio. For a ratio W:H, the width is diagonal x W / sqrt(W^2 + H^2) and the height is diagonal x H / sqrt(W^2 + H^2). A 27-inch 16:9 monitor is therefore 23.53 inches wide and 13.24 inches tall, and a 20-inch 4:3 screen forms the classic 3-4-5 triangle: 16 by 12 inches. Ultrawide monitors are sold as 21:9 but are really 64:27 (2560 x 1080) or 43:18 (3440 x 1440), so both are offered. The comparison mode exposes a common surprise: a 34-inch 43:18 ultrawide has 32% more area than a 27-inch 16:9 monitor but is about 1% shorter, so text and video are no taller. Diagonals are entered in inches because that is how screens are sold; switch to metric for centimetres. This works in physical size - to scale pixel dimensions, use the aspect ratio calculator instead.

Calculation method

  • Width = d x W / sqrt(W^2 + H^2)
  • Height = d x H / sqrt(W^2 + H^2)
  • Area = width x height; comparison = area 2 / area 1
  • 1 in = 2.54 cm; 1 sq in = 6.4516 cm^2

Worked examples

27-inch 16:9 monitor

Inputs: 27 in, 16:9

Result: 23.53 x 13.24 in; 311.5 sq in

27 x 16 / sqrt(337) = 23.53 in.

Compare with a 34-inch ultrawide

Inputs: 34 in, 43:18 versus 27 in, 16:9

Result: 31.36 x 13.13 in; 132% of the area, 99% of the height

Wider but slightly shorter than the 27-inch screen.

Limitations

  • Gives the visible picture area only; bezels, frames and stands are not included.
  • Curved screens are treated as flat; the chord width is slightly less than the stated figures.
  • Diagonals must be entered in inches.

Where publishers use it

  • Monitor and TV review sites comparing ultrawide and standard models
  • Desk-setup and home-office blogs checking whether a screen fits between speakers or under a shelf
  • Projector and home-cinema sites working out screen width for a given diagonal
  • Retail product pages answering how wide is a 65-inch TV
  • Gaming sites explaining field of view on 16:9 versus 21:9 displays
  • Boardroom and classroom AV integrators sizing a display so the back row can read slides

Questions

How wide is a 65-inch TV?

A 65-inch 16:9 TV is 56.7 inches (144 cm) wide and 31.9 inches (81 cm) tall, before the frame and stand. Check the maker's dimensions for the full product size.

Is a 34-inch ultrawide bigger than a 27-inch monitor?

Wider and larger in area, but not taller. A 34-inch 3440 x 1440 ultrawide is 31.4 x 13.1 inches; a 27-inch 16:9 is 23.5 x 13.2 inches. The ultrawide has 32% more area and 99% of the height.

Why are there two 21:9 options?

21:9 is a marketing name. 2560 x 1080 panels are 64:27 (2.37:1) and 3440 x 1440 panels are 43:18 (2.39:1); using the true ratio gives sizes accurate to about a tenth of an inch.

How is this different from the aspect ratio calculator?

The aspect ratio calculator works with pixel dimensions - resizing 1920 x 1080 to a new width, for example. This widget works with physical size from a diagonal in inches.

Will a 55-inch TV fit above my fireplace or on my sideboard?

Measure the gap, then compare it with the width here plus the bezel: a 55-inch 16:9 picture is 47.9 inches (121.8 cm) wide and 27 inches tall, and most frames add 0.3 to 1 inch on each side. A soundbar or wall bracket can add several inches of height.

What does doubling the diagonal do?

It doubles the width and height and quadruples the area. A 55-inch TV has (55/27)^2 = 4.15 times the area of a 27-inch monitor of the same ratio.

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A2Z Tools Screen Size Calculator
https://a2z.tools/embed/screen-size-calculator

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