A 27-inch 16:9 monitor's screen is 23.5 x 13.2 in (59.8 x 33.6 cm). A 34-inch 21:9 ultrawide's is 31.3 x 13.4 in (79.4 x 34 cm).
Monitor Math is a free calculator and comparison site for people choosing a monitor. It shows exact physical size, pixel density, and desk fit for any two screens. Measure the screen, plan the desk — before you buy. Type a diagonal and pick a resolution, and Monitor Math returns the real width, height, screen area, and pixel density in inches and cm, draws it to scale, and checks how it fits your desk.
How much bigger is a 32-inch monitor than a 27-inch?
The 32-inch monitor is 4.4 inches wider and 2.5 inches taller than the 27-inch monitor, with 40.5% more screen area: 27.9 x 15.7 in against 23.5 x 13.2 in.
For a screen with aspect ratio w:h, width = diagonal x w / √(w² + h²) and height = diagonal x h / √(w² + h²). A 27-inch 16:9 screen is 27 x 16 / 18.36 = 23.5 inches wide. Two monitors with the same diagonal can differ a lot in height, so check the shape as well.
Quick visual checks for the questions that are hard to judge from diagonal size alone: physical screen shape, desk span, and how wide resolutions compare with 4K.
Monitor size calculator and comparison: common questions
How the math works
How do I calculate monitor size?
A monitor's advertised size is its diagonal, but the useful numbers are width and height. Split the diagonal by the aspect ratio: width = diagonal × ratioW ÷ √(ratioW² + ratioH²), and height = diagonal × ratioH ÷ √(ratioW² + ratioH²). This calculator does it automatically — enter a diagonal and aspect ratio to get exact width, height, screen area, and pixel density in inches and centimeters.
How do I compare two monitor sizes?
Compare width, height and screen area, not the diagonal. A 27-inch 16:9 monitor is 23.5 × 13.2 inches; a 32-inch 16:9 is 27.9 × 15.7 inches, 40% more screen area for a 5-inch bigger diagonal. Shape matters too: a 34-inch 21:9 ultrawide is wider than the 32-inch (31.3 inches) but shorter (13.4 inches). Enter both screens above to see them overlaid to scale with the percentage difference in width, height and area.
Is a 49-inch super ultrawide bigger than a 40-inch ultrawide?
Wider, not taller. A 49-inch 32:9 is 47.2 × 13.3 inches; a 40-inch 21:9 is 36.8 × 15.8 inches. The 49-inch adds 10.4 inches of width and 8% more screen area, but the 40-inch is 2.5 inches taller, which matters for documents and code.
What are the dimensions of a 27-inch monitor?
A 27-inch 16:9 monitor is about 23.5 inches wide and 13.2 inches tall (59.8 × 33.6 cm), roughly 312 square inches of screen. Width and height depend on the aspect ratio, so a 27-inch 16:9 and a 27-inch ultrawide are not the same shape at the same diagonal.
How do I find monitor width and height from the diagonal?
Use the aspect ratio. For a 16:9 screen, width ≈ diagonal × 0.872 and height ≈ diagonal × 0.490. For other shapes (16:10, 21:9, 32:9, 3:2), the exact ratio changes those multipliers — the calculator applies the precise formula for any aspect ratio you enter.
What is PPI and how do I calculate it?
PPI (pixels per inch) measures sharpness: PPI = √(widthPx² + heightPx²) ÷ diagonal. A 27-inch 1440p panel is about 109 PPI, while a 27-inch 4K panel is about 163 PPI. Use the dedicated PPI calculator at /ppi-calculator for any size and resolution.
Do two monitors of the same size have the same dimensions?
Only if they share an aspect ratio. A 34-inch 21:9 ultrawide is far wider and shorter than a 34-inch 16:9 monitor. Aspect ratio changes both width and height even at an identical diagonal, which is why the calculator asks for the shape as well as the size. The aspect ratio calculator at /aspect-ratio-calculator shows the difference.
Start with the tool, then choose the page
Best entry points
Start with exact screen dimensions, then test the layout on your desk. Use the size guide for a single display, compare two monitors side by side, or place your choices in the 3D setup planner.
Jump straight to practical monitor comparisons: 27-inch vs 32-inch, first ultrawide jumps, 38/40/45/49-inch desk trade-offs, and setup layouts you can adjust in the builder.
