3 min readMarkdown
9:16, 16:9 and 4:5 in pixels: every size a short video needs
The exact pixel sizes for 9:16, 16:9, 4:5, 1:1 and 4:3, which shape each feed wants, and how to fix a video that came out the wrong shape.
An aspect ratio is a shape, not a size. 9:16 says the picture is 9 units wide for every 16 tall; it does not say how many pixels. The sizes below are the ones each feed actually asks for, so you can stop converting in your head.
The sizes
| Ratio | Shape | Standard size | Smaller | Larger |
|---|---|---|---|---|
| 9:16 | Vertical | 1080 × 1920 | 720 × 1280 | 2160 × 3840 |
| 16:9 | Horizontal | 1920 × 1080 | 1280 × 720 | 3840 × 2160 |
| 4:5 | Tall portrait | 1080 × 1350 | 864 × 1080 | 2160 × 2700 |
| 1:1 | Square | 1080 × 1080 | 720 × 720 | 2160 × 2160 |
| 4:3 | Classic | 1440 × 1080 | 960 × 720 | 2880 × 2160 |
9:16 in pixels is 1080 × 1920. 16:9 is the same rectangle turned on its side, 1920 × 1080. Every other row follows the same rule: pick the height, multiply by the ratio.
Which shape each feed wants
- TikTok, Instagram Reels and YouTube Shorts: 9:16, 1080 × 1920. Anything wider gets bars or a crop.
- X: 9:16 travels best in the feed; 720 × 1280 is the safe upload size.
- Instagram feed posts: 4:5, 1080 × 1350. It is the tallest shape the grid shows uncropped, so it takes the most room on a phone.
- YouTube, a website header, a presentation: 16:9, 1920 × 1080.
- A thumbnail grid or a profile: 1:1, 1080 × 1080.
Working one out yourself
Width = height × (first number ÷ second number). A 9:16 video 1280 pixels tall is 1280 × 9 ÷ 16 = 720 wide. Keep both numbers even: video encoders want even dimensions, and an odd one is often rounded for you, which shifts the frame by a pixel.
An odd size like 1500 × 900 reduces to 5:3. It is not one of the shapes above, so a feed will letterbox or crop it.
When a video came out the wrong shape
You have two honest choices, and they lose different things:
- Crop: fill the new frame and cut off the edges. Good when the subject is in the middle; bad when the edges carry text.
- Pad: keep every pixel and add bars or a blurred fill. Good for a screen recording; it looks small on a phone.
Whichever you choose, check the safe zone: on TikTok, Reels and Shorts the caption, the buttons and the account name sit on top of the bottom and right of the frame, so words placed there are covered.
Do it in Kuro
- Type any two numbers into the aspect ratio calculator to get the ratio, or a ratio and one side to get the other.
- Reshape a finished clip to 9:16, 4:5, 1:1 or 16:9 with Resize a video; it runs in your browser and the file is never uploaded.
- Drop the result on the safe-zone checker before you post.
- Or skip the fix: in /create, choose 9:16 before you generate, and the clip comes out the right shape the first time.
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