Video aspect ratio calculator
Enter a video's width and height to get its aspect ratio, calculate a new size that keeps the same shape, and see exactly how much of the frame survives a crop to 9:16, 1:1, 4:5 or any other format.
Free · no signup · runs in your browser, nothing is uploaded.
Find the aspect ratio
16:9 (1.778)
Resize without distortion
1080 × 608
Height rounded to an even number, which most video encoders require.
Crop to another format
608 × 1080
A center crop keeps 31.7% of the width. Anything outside the crop is lost, so track the subject or stack the frame instead of cropping the center.
Common sizes
| Ratio | Full HD | Use |
|---|---|---|
| 9:16 | 1080 × 1920 | TikTok, Reels, Shorts, Stories |
| 16:9 | 1920 × 1080 | YouTube, landscape video |
| 1:1 | 1080 × 1080 | Feeds, LinkedIn, X |
| 4:5 | 1080 × 1350 | Instagram & Facebook feed, LinkedIn |
| 4:3 | 1440 × 1080 | Older cameras, some screen recordings |
How to calculate an aspect ratio
- Enter the width and height of your video in pixels (for example 1920 and 1080).
- Read the simplified ratio: 1920×1080 is 16:9.
- To resize, enter a new width; the calculator gives the matching height, rounded to an even number for encoders.
- To reformat, pick a target such as 9:16 to see the crop size and how much of the original frame it keeps.
How aspect ratio is calculated
Aspect ratio is width divided by height, written as the simplest whole-number pair. Divide both numbers by their greatest common divisor: 1920 and 1080 share 120, so 1920×1080 becomes 16:9. 1080×1920 is 9:16, and 1080×1350 is 4:5.
Converting 16:9 to 9:16
A 1920×1080 video cropped to vertical becomes 608×1080, keeping only about a third of the width. That's why a plain center crop often cuts people or gameplay out of frame. Better options are tracking the speaker so the crop follows them, stacking two parts of the frame (facecam above gameplay), or placing the landscape video over a blurred background.
OptimaClip's Smart Reframe tracks faces automatically and exports every clip in 9:16, 1:1, 4:5 and 16:9.
Which aspect ratio for which platform
TikTok, Instagram Reels, YouTube Shorts and Stories use 9:16. YouTube long-form uses 16:9. Instagram and Facebook feed posts look best at 4:5, and LinkedIn and X feeds handle 1:1 and 4:5 well. See the social video specs page for length limits too.
FAQ
What aspect ratio is 1920×1080?
16:9.
What aspect ratio is 1080×1920?
9:16, the vertical format used by TikTok, Reels and Shorts.
What size is 4:5?
1080×1350 pixels at full HD width.
How do I convert a horizontal video to vertical without losing the subject?
Track the subject so the 9:16 crop follows them, or stack parts of the frame. A fixed center crop keeps only about a third of a 16:9 frame's width.
Skip the manual steps
OptimaClip turns a long podcast, stream or webinar into captioned vertical clips that already sit inside every platform's safe zone, exported in 9:16, 1:1, 4:5 and 16:9 and scheduled to 8 platforms.