Aspect Ratio Calculator
Calculate missing dimensions from an aspect ratio, convert between ratios, and use quick presets for common formats.
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Presets
Ratio
:
Simplified
Known Width → Find Height
→
Known Height → Find Width
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Common Aspect Ratios
| Ratio | Decimal | Common Use |
|---|---|---|
| 16:9 | 1.78 | HD video, YouTube, most monitors |
| 4:3 | 1.33 | Traditional TV, old monitors, some cameras |
| 1:1 | 1.00 | Instagram square posts, icons, avatars |
| 3:2 | 1.50 | DSLR / mirrorless camera standard, 35mm film |
| 2:3 | 0.67 | Portrait photography, Pinterest pins |
| 9:16 | 0.56 | Instagram Stories, TikTok, Reels, mobile video |
| 21:9 | 2.33 | Ultrawide monitors, cinematic video |
| 5:4 | 1.25 | Some monitors, medium format photography |
Understanding Aspect Ratios
An aspect ratio describes the proportional relationship between an image's width and height. An image that is 1920 pixels wide and 1080 pixels tall has an aspect ratio of 16:9 (since 1920/1080 simplifies to 16/9).
Maintaining the correct aspect ratio when resizing is important to avoid stretching or squashing images. In GIMP, the Scale Image dialog has a chain link icon between the width and height fields - Clicking it locks the aspect ratio so both dimensions scale together.