★ Change Aspect Ratio
Free online video aspect ratio changer
Turn a landscape video into vertical, square or 4:5 (or the reverse) — right in your browser, with no upload.
Upload a video (MP4, MOV, WEBM, MKV…)
Reels, TikTok and Shorts want vertical 9:16, feed posts often want 1:1 or 4:5, and YouTube wants 16:9. This tool reframes a video to the ratio you pick and lets you choose how the extra space is handled: a blurred copy of the video behind it, plain black bars, or cropping to fill the frame.
Everything runs on your own device with WebAssembly, so the video stays private. Reframing re-encodes the video, so it takes longer than simple tools like trimming — short clips finish fast, long ones can take a few minutes.
Why use this tool?
Four popular ratios
9:16 (720×1280), 1:1 (720×720), 4:5 (720×900) and 16:9 (1280×720) cover the main social and video platforms.
Three ways to fill the frame
Blurred background keeps the whole picture visible, black bars are the plainest option, and crop fills the frame by trimming the edges.
Private by design
Your video is processed locally in the browser and never uploaded.
Frequently asked questions
Which ratio should I choose?
Use 9:16 for Reels, TikTok and YouTube Shorts, 1:1 or 4:5 for feed posts, and 16:9 for regular YouTube videos. Check each platform's current recommendation, as they change.
What is the difference between the three fit options?
Blurred background shows the full video over a blurred, enlarged copy of itself. Black bars shows the full video with plain bars. Crop fills the whole frame but cuts off the edges of the picture.
Will the quality change?
The video is re-encoded at a fixed output size, so there is some quality trade-off, and small videos are enlarged to the target size.
Is my video uploaded anywhere?
No. The conversion runs entirely on your device using WebAssembly.