Aspect Ratio Calculator
Reduce any screen resolution to its aspect ratio — divide width by height and simplify. Add a diagonal size to convert that ratio into exact width and height in inches and centimeters.
Aspect ratio
16:9
Decimal
1.778:1
Class
16:9 widescreen
How aspect ratio is calculated
Aspect ratio is width divided by height, reduced to whole numbers by their greatest common divisor. 2560 × 1440 divides down to 16:9; 3440 × 1440 reduces to 43:18, which is marketed as 21:9. The ratio sets the shape — combine it with a diagonal size and the exact physical width and height follow from the geometry.
Common resolutions and their aspect ratios
| Resolution | Exact ratio | Marketed as |
|---|---|---|
| 1920 × 1080 | 16:9 | Widescreen / 4K class |
| 2560 × 1600 | 16:10 | Productivity / laptop |
| 2560 × 1080 | 64:27 | 21:9 ultrawide |
| 3440 × 1440 | 43:18 | 21:9 ultrawide |
| 5120 × 1440 | 32:9 | Super ultrawide |
| 3840 × 2560 | 3:2 | Tall productivity |
Frequently asked questions
How do I calculate an aspect ratio?
Divide the width by the height, then reduce to whole numbers. For pixel dimensions, divide both by their greatest common divisor: 2560×1440 reduces to 16:9, and 3440×1440 reduces to 43:18 (marketed as 21:9). This calculator reduces any width and height to its simplest ratio and its decimal form.
What aspect ratio is 2560x1080 or 3440x1440?
2560×1080 is 64:27, and 3440×1440 is 43:18 — both are marketed as 21:9 ultrawide even though the exact ratios differ slightly. 5120×1440 is 32:9 (super ultrawide), and 3840×2160 (4K) is 16:9.
Does aspect ratio change a monitor's physical size?
Yes. At the same diagonal, a wider aspect ratio makes the screen wider and shorter. A 34-inch 21:9 monitor is much wider and less tall than a 34-inch 16:9. Enter a diagonal alongside the ratio to see the exact width and height in inches and centimeters.
What are the most common monitor aspect ratios?
16:9 (standard widescreen and 4K), 16:10 (productivity and many laptops), 21:9 (ultrawide), 32:9 (super ultrawide), 3:2 (tall productivity panels), and 4:3 (legacy). Aspect ratio determines the shape; the diagonal determines the overall size.