Video aspect ratio converter
This video aspect ratio converter changes any video to 9:16, 16:9, 1:1, 4:5 or 4:3 right in your browser. Crop it, add bars or use a blurred background, then download an MP4. No signup, no watermark and no upload.
New aspect ratio
How to fill the frame
Output size
Your video is processed in your browser and never uploaded anywhere. No signup, no watermark. Long or 4K videos take longer and use more memory.
Which aspect ratio each platform uses
| Where | Aspect ratio | What the platform says |
|---|---|---|
| YouTube videos | 16:9 | The standard on a computer (YouTube Help) |
| YouTube Shorts | 9:16 or 1:1 | Square or vertical videos up to three minutes count as Shorts (YouTube Help) |
| Instagram Reels | 9:16 fills the screen | Accepts 1.91:1 to 9:16, minimum 720 pixels and 30 FPS (Instagram Help) |
| TikTok | 9:16 | Avoid videos outside full 9:16 portrait where possible (TikTok for Business) |
| Facebook and Instagram ads | 1:1 or 4:5 in feed, 9:16 in Stories and Reels | 16:9 is recommended for in-stream video (Meta Business Help) |
| LinkedIn video ads | 16:9, 1:1, 4:5 or 9:16 | Up to 1920 x 1080 for 16:9 and 1080 x 1920 for 9:16 (LinkedIn ads guide) |
Sources linked in the table, checked 2 November 2026. Platforms change these, so check before a big campaign.
Crop, bars or blurred background: which to choose
| Option | Best for | The trade-off |
|---|---|---|
| Crop to fill | Talking heads and any subject that stays in one place | Cuts off the sides or top and bottom, and uses fewer pixels |
| Blurred background | Moving subjects, gameplay and footage where the whole frame matters | The picture is smaller, so fine detail is harder to see on a phone |
| Fit with bars | Screen recordings, slides and product demos | Same smaller picture, and plain bars can look unfinished in a vertical feed |
How to change a video's aspect ratio
- Upload or drop your video. It loads on your device, so nothing is sent to a server.
- Pick the new aspect ratio, such as 9:16 for Shorts, Reels and TikTok.
- Choose how to fill the frame, and if you are cropping, drag the preview to keep the subject in shot.
- Play the preview to check the whole video, because the crop does not move during playback.
- Press Convert, keep the tab open until it finishes, then download the MP4.
When a converter is not enough
A single fixed crop suits simple footage. Interviews with two speakers, product demos and fast edits usually need reframing shot by shot, with captions moved clear of each platform's buttons. Our guide to video aspect ratios for social media covers safe zones and how to plan for several formats, and our short-form video editing service handles the reframing for you. To work out exact dimensions, use the aspect ratio calculator.
Frequently asked questions
How do I change a video's aspect ratio without cropping?
Choose Fit with bars or Blurred background. Both keep the whole frame and fill the empty space around it, so nothing is cut off. The picture appears smaller than a full-frame crop would.
How do I convert a 16:9 video to 9:16?
Upload the video, choose 9:16, then pick how to fill the frame. Crop to fill keeps a vertical slice of the picture, which you position by dragging the preview. Blurred background keeps the whole wide frame in the middle. Press Convert and download the MP4.
Is my video uploaded anywhere?
No. The conversion runs on your device using your browser's built-in video tools, and the file never leaves it. That also means your device does the work, so long videos take longer on slower machines.
Does it add a watermark or need a signup?
No. There is no watermark, signup or payment.
What file formats does it support?
It exports MP4 and accepts common video files such as MP4, MOV and WebM. What your browser can read depends on its codecs, so if a file does not work the tool tells you, and an H.264 MP4 is the safest input.
Will changing the aspect ratio reduce quality?
A crop uses fewer of the original pixels. Cropping 1920 x 1080 to 9:16 keeps a slice about 608 x 1080, which is then scaled up to 1080 x 1920, so it looks softer than the original. Cropping 3840 x 2160 keeps about 1215 x 2160, which holds up much better. The video is also re-encoded, which adds a small quality loss.
What size should a 9:16 video be?
1080 x 1920 is the common export size, and this tool's default. A 720 x 1280 export makes a smaller file. Instagram's minimum for Reels is 720 pixels.
Can it follow a moving person when cropping?
No. The crop stays in one position for the whole video. It works when the subject stays in place, such as a talking head. If the subject moves, use Blurred background, or have the video reframed shot by shot in an editor.