How to use the Video Aspect Ratio Converter tool
- Choose your video.
- Pick the size or format you need. Choose how to fill the frame if the shape changes.
- Press Resize video.
- Check the preview and download the resized file.
About this tool
Aspect ratio is the shape of the picture: 16:9 is widescreen, 9:16 is vertical, 1:1 is square and 4:5 is the portrait ratio favored by Instagram's feed. When you put a video into a different shape you must decide what to do with the mismatch, and this tool offers three answers.
Blurred background shows the whole video in the middle over an enlarged, softly blurred copy of itself. Black bars is the classic letterbox. Fill zooms in and crops the edges so the picture covers the whole frame. Pick a size or keep the original scale.
Why use ToolsCrow for this
- Eight ratios. 16:9, 9:16, 1:1, 4:5, 4:3, 3:4, 2:3, 21:9.
- Blurred background. Looks intentional, not empty.
- Choose the size. Or keep the original.
- Private. No upload.
Good to know
- The blur background needs a browser that supports canvas filters (Chrome, Edge and Firefox do). In others the background falls back to black.
Frequently asked questions
Is my video uploaded to a server?
No. Everything runs inside your browser tab using your own device's video hardware. Your file is never sent to ToolsCrow or anyone else, which also means there is no waiting for an upload and it keeps working if your connection drops after the page has loaded.
Is it really free? Is there a watermark?
It is free with no sign-up, no watermark and no daily limits. The only limits are the ones your device sets: memory and processing power.
How large a video can I use?
Because the video is processed on your device, the limit is your device's memory rather than a server quota. Phone clips of several hundred MB are fine on most devices, and desktop computers usually handle 1 to 2 GB. Files over about 4 GB are not supported.
Which browsers work best?
Current Chrome, Edge and Safari (16.4 or newer, including iPhone and iPad) work best because they include the WebCodecs video engine. Recent Firefox versions work for many files. Older browsers fall back to a much slower real-time mode or may not work at all.
How do I turn a horizontal video into a vertical one?
Choose 9:16 and pick "Blurred background" to keep everything visible, or "Fill" to crop the sides and zoom in.
Which ratio should I use for Instagram?
9:16 for Reels and Stories, 4:5 for feed videos, 1:1 for square posts.
Related video tools
- TikTok Video ResizerFit a video to TikTok's recommended sizes.
- Instagram Video ResizerFit a video to Instagram's recommended sizes.
- YouTube Shorts Video ResizerFit a video to YouTube Shorts's recommended sizes.
- Video CropperDrag the crop box, pull a corner, or pick a ratio such as 1:1 for Instagram or 9:16 for TikTok.
- Custom Video DimensionsType the exact width and height you need.
- Video ResizerScale a video down to 1080p, 720p, 480p or 360p and keep the proportions.
- Resize Video by PercentageShrink or enlarge a video by a percentage of its current size.
More in resize video (20 tools), or browse all video tools..