Change any video to custom dimensions or a ready-made preset — square, vertical 9:16, 1080p and more. Crop, letterbox, or stretch, then download. Everything runs in your browser; nothing is uploaded.
Aspect ratio locked to the source — editing one side adjusts the other.
Rendering happens in real time, so a clip takes about as long as its duration to process. Keep this tab active while it renders.
The Video Resizer changes the dimensions of any video to an exact size or a ready-made preset — right in your browser, with no upload, no watermark, and no software to install.
Drop in a clip, type the width and height you want or pick a preset such as square 1:1, vertical 9:16, 1080p, or 4K, then choose how the frame should be filled. The tool decodes your video, redraws every frame onto a canvas at the new size, and re-encodes it locally using your browser's built-in recorder. Because none of this touches a server, your footage stays completely private. People use it to:
The three fit modes give you full control. Stretch forces the exact size you type, which can distort the picture. Contain fits the whole video inside the new frame and pads the gaps with a colour of your choice. Cover fills the frame edge to edge and crops whatever spills over, so nothing is squashed. Output is WebM by default because it plays everywhere in modern browsers; on Safari an MP4 option appears too. One honest trade-off of doing everything in the browser: re-encoding runs in real time, so a thirty-second clip takes about thirty seconds to render.
No. The video is decoded, re-drawn at the new dimensions, and re-encoded entirely inside your browser using the canvas and MediaRecorder APIs. The file never leaves your device.
WebM (VP9 or VP8 video with Opus audio) works in every modern browser. If your browser supports MP4 recording — mainly Safari — an MP4 option appears as well. WebM plays in browsers and most editors, and can be converted to MP4 if you need maximum compatibility.
Browsers can only re-encode video in real time through the MediaRecorder API, so a 30-second clip takes roughly 30 seconds to render. This is the trade-off for doing everything locally with no upload and no software to install.
Stretch forces the video to the exact width and height you set, which can distort it. Contain fits the whole video inside the new size and fills the leftover space with a solid colour (letterboxing). Cover fills the entire frame and crops whatever overflows, so nothing is distorted but edges may be cut.
Yes. Pick the 9:16 vertical preset (1080×1920) and choose Cover to crop the sides, or Contain to keep the full frame with bars above and below. This is ideal for Reels, TikTok, YouTube Shorts, and Stories.
Any re-encode is lossy, but you can choose High quality to keep a generous bitrate. Downscaling to smaller dimensions generally looks clean; upscaling to larger dimensions cannot add detail that was not in the source.
There is no hard limit, but everything runs in your browser's memory, so very long or very high-resolution videos use more RAM and take longer. For big files, resize on a desktop browser rather than a phone.