Video Resizer
Resize a video to new dimensions for any platform or device, in your browser. Free, private, no signup or upload.
About the Video Resizer
This free video resizer scales a video to new dimensions — shrink a 1080p clip to 720p to save space, downscale for a specific platform, or set a custom width and height. Enter both dimensions, or set just the width and let the height follow automatically to keep the aspect ratio.
Resizing runs in your browser using FFmpeg WebAssembly, so your video is never uploaded. The engine (about 30 MB) is downloaded from a CDN on first use and cached, so the first resize is the slow one. The output is a widely-compatible H.264 MP4 with a web-friendly yuv420p pixel format.
Downscaling reduces file size and keeps quality high; upscaling to larger dimensions cannot add real detail and will look softer, so it is best used only when a platform requires a minimum size. Videos up to 100 MB are supported.
How to Use the Video Resizer
- 1Choose a video file, up to 100 MB.
- 2Enter a target width, and a height (or leave height blank to keep the aspect ratio).
- 3Click Resize Video and wait for the progress bar.
- 4Preview the resized video and download it.
Frequently Asked Questions
Is my file uploaded to a server?
No. All processing runs in your browser using FFmpeg compiled to WebAssembly. Your file never leaves your device — only the converter engine is downloaded, once.
Why is the first run slow?
The first time you use any converter here, the browser downloads the FFmpeg core (about 30 MB) from a CDN and compiles it. It is then cached for the session, so later runs are much faster.
How do I keep the aspect ratio?
Enter only the width and leave the height blank — the tool calculates a matching height automatically so the video is not stretched. Set both if you deliberately want a specific shape.
Can I make a video larger?
You can, but upscaling cannot add detail that is not in the source, so the result looks softer. Downscaling is where resizing shines — smaller files with crisp quality.
Is there a file size limit?
Yes, 100 MB per file. Because everything runs in your browser's memory, very large files can be slow or run out of memory. Trim long clips first if you hit the limit.