Resize Video
Change resolution or aspect ratio with platform presets, filling the space with a blurred copy or a colour.
Free, no uploads, no sign-up. Runs 100% in your browser.
How Resize Video works
Video work runs in ffmpeg.wasm, the FFmpeg toolkit compiled to WebAssembly (GPL build, loaded as a separate engine file of about 30 MB the first time, then cached).
Input: MP4, MOV, WEBM, MKV, AVI. Output: MP4.
How to use Resize Video
- Drop a video onto Resize Video.
- The first run downloads the ffmpeg engine (about 30 MB, once).
- Set your range, format or quality options.
- Process it (progress is shown live), then download.
Tips
- Shorter clips and lower resolutions process much faster.
- Processing speed depends on your CPU; plug in laptops for long jobs.
- Keep the tab in the foreground while encoding.
Resize Video FAQ
- Are my files uploaded?
- No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
- Is it free? Are there limits or watermarks?
- Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
- Does it work offline?
- Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.
Related tools
- Crop Video: Crop a video visually with aspect presets for Reels, Shorts and TikTok (9:16), square (1:1) and portrait (4:5).
- Video Compressor: Compress videos with quality presets and target resolution.
- Picture in Picture & Background: Overlay a second video or image, place a video on a coloured or image background, or add a slow zoom.
- Video Trimmer: Trim and cut clips with a visual timeline, no re-upload.