Aspect Ratio Calculator
Simplify a width and height to an aspect ratio like 16:9, work out a missing side from a ratio, and browse common ratios and resolutions.
Find the aspect ratio
Enter a width and height to see the simplified ratio.
Resize to a ratio
e.g. 16:9, 4/3 or 2.39
Enter either the width or the height and the other is calculated.
Common ratios
| Ratio | Typical use | Common resolutions |
|---|---|---|
| TVs, monitors, YouTube video | 1280×720, 1920×1080, 2560×1440, 3840×2160 | |
| Laptop and desktop displays | 1280×800, 1920×1200, 2560×1600 | |
| Older monitors, slides, iPad | 640×480, 1024×768, 1600×1200, 2048×1536 | |
| Camera photos, Surface laptops | 1080×720, 2160×1440, 6000×4000 | |
| Social posts, profile pictures | 1080×1080, 2048×2048 | |
| Older LCD monitors | 1280×1024 | |
| Ultrawide monitors, cinema (really about 64:27 or 43:18) | 2560×1080, 3440×1440, 5120×2160 | |
| Super-ultrawide monitors | 3840×1080, 5120×1440 | |
| Phone screens, panoramas | 2160×1080, 4096×2048 | |
| Stories, short video, vertical phone video | 720×1280, 1080×1920 | |
| Instagram portrait posts | 1080×1350 | |
| Portrait photos, tablets upright | 768×1024, 1536×2048 | |
| Portrait prints, posters | 1000×1500, 4000×6000 |
How to use
- Under “Find the aspect ratio”, enter a width and height (e.g. 1920 and 1080) to get the simplified ratio 16:9, its decimal value and whether it is close to a common ratio.
- Under “Resize to a ratio”, enter a ratio (e.g. 16:9, 4/3 or 2.39), then either the width or the height; the other side is calculated and previewed.
- Click a ratio in the “Common ratios” table to use it, and see typical resolutions.
FAQ
How is an aspect ratio simplified?
Divide the width and height by their greatest common divisor. For 1920 × 1080 that is 120, giving 16:9. Decimals work too: 2.35:1 simplifies to 47:20.
Why isn’t 1366 × 768 exactly 16:9?
1366 × 768 simplifies to 683:384, about 1.779, which is very close to but not the same as 16:9 (1.778). The tool reports it as “close to 16:9”. Many common resolutions are approximations like this.
What ratio is a 21:9 ultrawide monitor really?
21:9 is a marketing name. 2560 × 1080 is really 64:27 (about 2.37) and 3440 × 1440 is 43:18 (about 2.39); both are only close to 21:9 (about 2.33).
What if the calculated size has decimals?
Pixels must be whole numbers, so the tool rounds half up and also shows the exact value: at 16:9, a height of 500 needs a width of 888.89, rounded to 889. For an exact fit, pick sizes the ratio divides evenly, such as widths that are multiples of 16 for 16:9.
Is my data uploaded?
No. Everything is calculated in your browser, with no network connection needed.
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