Aspect ratio calculator
Reduce a resolution to its simplest ratio using the greatest common divisor, and see which of the common device shapes it is closest to.
Resolution
portrait
Result
- Simplified ratio
- 9:20
- Decimal (long ÷ short)
- 2.2222
- Orientation
- portrait
- Closest common ratio
- 20:9 — Modern Android phone
Reading phone aspect ratios
Phone ratios have stretched steadily: 16:9 was standard until 2017, then 18:9 arrived with the first tall phones, and most modern Android devices sit between 19.5:9 and 20:9. Sony has stayed at 21:9 for several generations, which is why Xperia screenshots look dramatically taller than other Android phones at the same physical size.
The ratio affects layout more than density does. A 21:9 viewport gives you far more dp of height at the same width, so vertically centred content drifts and sticky headers reveal more or less of the page depending on the device. Foldables are the opposite extreme: their inner displays are close to square, which breaks any layout that assumes width is always much smaller than height.
The simplified ratio uses the greatest common divisor of the two dimensions, so 1080×2400 reduces to 9:20 rather than the 20:9 you will see quoted in marketing material. Both describe the same panel; the site reports it with the short edge first to stay consistent when comparing portrait and landscape.
Common screen ratios and what they mean
| Ratio | Typical resolution | Where you see it |
|---|---|---|
| 4:3 | 2048 × 1536 | Older tablets, iPad, camera sensors |
| 16:9 | 1920 × 1080 | Phones up to 2017, most video content |
| 16:10 | 2560 × 1600 | Tablets, laptops, Steam Deck |
| 18:9 | 1440 × 2880 | First tall phones, 2017–2018 |
| 19.5:9 | 1170 × 2532 | Many 2020-era flagships |
| 20:9 | 1080 × 2400 | The dominant modern Android shape |
| 21:9 | 1644 × 3840 | Sony Xperia, ultrawide monitors |
Why a 20:9 screen is not 2.22× tall
The ratio describes the panel, not the window your app draws into. System bars, cutouts and gesture insets all remove space, so a 20:9 panel gives a layout closer to 19.4:9 of usable height once the status bar and navigation bar are subtracted. Tools that measure the window instead of the display will report a slightly squatter ratio than the marketing spec, and both numbers are correct for their own definition.
If you are adjusting dp values for a specific phone, the device database lists each panel's resolution, ppi and dp viewport together, and the DPI calculator shows how much dp width and height a given resolution produces at its density.