Resize Video Online

Resize a video for a presentation, social post, short-form platform, or custom player without uploading the source to a remote conversion service. The visual preview makes the most important choice clear before processing: whether the video should fill the destination frame or remain completely visible.

Reframe video with Fill or Fit

Choose Fill when the output must cover every pixel of the destination canvas. The video keeps its original proportions, scales until the canvas is covered, and is then cropped from the center. This works well for full-screen vertical videos and feed posts, but content close to the left, right, top, or bottom edge may be removed.

Choose Fit when preserving the entire frame matters more than filling the canvas. The video scales inside the target dimensions and any remaining area uses your selected background color. Fit is useful for screen recordings, slides, demonstrations, and footage where captions or people near the edge must not be cropped.

Destination presets cover 16:9 landscape, 9:16 Reels and TikTok video, 1:1 square posts, 4:5 portrait posts, and 1280 × 720 HD. You can also enter a custom width and height. Values are normalized to even pixels because common H.264 playback formats are most reliable with even frame dimensions.

Avoid accidental low-quality enlargement

Upscaling is disabled by default. If the source is too small to fill a larger destination, the tool centers it with padding instead of inventing detail through enlargement. Enable Allow upscaling only when exact edge-to-edge dimensions are required and you accept that the result may look softer. The summary under the preview shows the actual scale and whether the export will crop or pad.

The finished file is an MP4 with H.264 video and AAC audio for broad compatibility. Resizing requires re-encoding, so long 4K footage will take more time and browser memory than short clips. Keep the tab open during processing, preview the result when it finishes, and download it directly. The original file remains unchanged throughout the workflow.

All processing runs locally through FFmpeg compiled to WebAssembly. Your media stays on your device, making this workflow suitable for private drafts, internal recordings, and personal footage that you do not want to send to an unknown server.