Aspect Ratio Calculator
Resize while keeping the ratio — with presets for video, social and OG images.
Dimensions
1,920 × 1,080
simplifies to 16:9 · 1.7778 : 1
Preview of a 16 by 9 rectangle. Height 56 percent.
Jump to a common size
Resize an image or video frame to a new width or height while keeping the exact same aspect ratio, so nothing looks stretched or squashed. Includes one-click presets for common video, social media, and Open Graph image dimensions.
Enter any two of width, height, or ratio and the third is calculated automatically, which also makes this useful for reverse-engineering the ratio of an existing image.
Ratios worth knowing
| Ratio | Typical dimensions | Used for |
|---|---|---|
| 16:9 | 1920×1080, 1280×720 | Video, YouTube, most screens |
| 1.91:1 | 1200×630 | Open Graph / link preview images |
| 1:1 | 1080×1080 | Square social posts, avatars |
| 4:5 | 1080×1350 | Portrait feed posts |
| 9:16 | 1080×1920 | Stories, Reels, Shorts |
| 3:2 | 1620×1080 | Most DSLR photography |
| 4:3 | 1024×768 | Older displays, many tablets |
| 21:9 | 2560×1080 | Ultrawide monitors, cinematic video |
Letterboxing, pillarboxing and cropping
When source and target ratios don't match, something has to give. Letterboxing adds bars above and below (a 16:9 video in a 4:3 frame); pillarboxing adds them to the sides. Cropping fills the frame but throws away part of the image — which is why faces get cut off when a landscape photo is auto-cropped to a square thumbnail.
If you know a design will be cropped to several ratios, keep the important content inside a centred 'safe area' that survives the tightest crop. For a design shown at both 16:9 and 9:16, that safe area is roughly a centred square.
Frequently asked questions
- How do I find the aspect ratio of an existing image?
- Enter its width and height, and the tool reduces them to the simplest ratio (e.g. 1920×1080 becomes 16:9).
- What's a safe aspect ratio for social media posts?
- 1:1 (square) and 4:5 (portrait) work well across most platforms' feeds; use the presets to jump straight to platform-specific dimensions.
- Will resizing with a locked ratio ever distort the image?
- No — locking the ratio guarantees the output dimensions are proportional to the original, so there's no stretching.
- What size should a link preview image be?
- 1200×630 (1.91:1) is the widely supported standard for Open Graph and Twitter cards. Keep text well inside the edges, as some platforms crop slightly.
- Why does my 1920×1080 image look different on a phone?
- Phones are tall, so a 16:9 landscape image occupies a small strip of the screen or gets cropped by the app. Export a separate 9:16 or 4:5 version for mobile-first placements.