Resize video for social media
Pick the platform format, choose whether the picture fills the frame or fits inside it, and save. The video is converted to MP4 on your device.
How to use it
- Drop one or more videos.
- Choose a format such as Vertical 9:16.
- Choose Fill the frame or Fit inside.
- Click Start and download the MP4.
Frequently asked questions
What size should a TikTok or Reels video be?
1080 × 1920 pixels, a 9:16 vertical frame. The Vertical preset exports exactly that.
Fill the frame or fit inside?
Fill the frame crops whatever sticks out and leaves no bars. Fit inside keeps the whole picture and adds black bars where the shapes differ.
Is there a file size limit?
No fixed limit. The video is read in small slices and the result is streamed to your disk, so even multi-gigabyte files work without filling up memory.
Is my video uploaded to a server?
No. The file is read and written inside your browser tab using WebCodecs — nothing is uploaded, there is no account and no watermark. Once loaded, the page also works offline.