Aspect Ratio Calculator
Find the ratio from a width and height, or calculate the missing side for a given ratio.
Aspect ratio
16:9
Decimal: 1.778:1 · Width ÷ height = 1.7778
This tool is for information only. For print and professional design work, check pixel values in your own software as well.
What is an aspect ratio?
An aspect ratio is the width of an image divided by its height, written as two numbers. 1920×1080 is 16:9 because dividing both numbers by 120 leaves 16 and 9. The ratio does not depend on size: 1280×720 and 3840×2160 are both 16:9.
Ratio = width ÷ heightSimplest form: divide both numbers by their greatest common divisorMissing height = width × ratio height ÷ ratio widthMissing width = height × ratio width ÷ ratio heightWorked example: the greatest common divisor of 1920 and 1080 is 120. 1920 ÷ 120 = 16 and 1080 ÷ 120 = 9, so the ratio is 16:9. For a width of 1280 the height is 1280 × 9 ÷ 16 = 720.
Common aspect ratios
These are the ratios you meet most often on screens, video and photos.
| Ratio | Decimal | Typical use | Example resolution |
|---|---|---|---|
| 16:9 | 1.78 | Monitors, TVs, YouTube video | 1920×1080 |
| 4:3 | 1.33 | Older TVs and monitors, iPad | 1024×768 |
| 1:1 | 1.00 | Square posts and profile images | 1080×1080 |
| 3:2 | 1.50 | Photography cameras | 3000×2000 |
| 9:16 | 0.56 | Vertical video (Reels, Shorts, TikTok) | 1080×1920 |
| 21:9 | 2.33 | Ultrawide monitors, cinema | 2560×1080 |
When the ratio does not simplify
Some resolutions, such as 1366×768, are not exactly 16:9. Reducing them gives large numbers like 683:384. In that case the calculator shows the closest common ratio and how far off it is as a percentage. For 1366×768 the gap is below 0.1%, so it counts as 16:9 in everyday use.
Resizing an image without distorting it
To scale an image, find its current ratio first, then enter the new width or height in the 'Find the missing side' tab. The result keeps the image from stretching or squashing. If the answer has decimals, round to the nearest whole pixel.