Resize Video
Change video resolution to 4K, 1080p, 720p, 480p or exact pixel dimensions, keeping the aspect ratio.
Free · No upload · 100% on your device
Resize Video
Choose videos, or drop them here.
MP4, MOV, MKV, WebM, AVI and more · No size or length limit. Nothing is uploaded.
100% on your device
How to use Resize Video
- Choose your videos, or drop them on the page.
- Pick the settings in the side panel.
- Select “Resize video”. The first use downloads the video engine once.
- Download the result. Your original file is left unchanged.
Private by design. Your files are processed in this browser tab and are never uploaded to KittySuite.
About Resize Video
The presets set the shorter side, so portrait phone videos stay portrait. Custom sizes fit the whole picture inside the frame and fill any spare space with black bars instead of stretching it. Resized videos are saved as MP4 with H.264, which plays almost everywhere.
Processing happens in this tab with FFmpeg compiled to WebAssembly; your files are never uploaded. The first video or audio tool you use downloads the 10 MB engine once and keeps it cached for next time. Long or high-resolution videos take longer than on a desktop editor, especially on phones, where files are processed one at a time to stay within memory. Keep the tab open until the download appears.
Resize Video: frequently asked questions
How do I change a video’s resolution?
Choose the video and a size: 4K, 1080p, 720p, 480p, 360p or a custom width and height. The result is an MP4 with H.264.
Will a portrait phone video stay portrait?
Yes. The presets set the shorter side, so vertical videos stay vertical.
Will a custom size stretch my video?
No. The whole picture is fitted inside the frame and any spare space is filled with black bars.
Does upscaling to 4K improve quality?
No. A larger resolution adds pixels but cannot add detail that was not recorded.