Resize video while keeping its aspect ratio
Resize video by changing its frame width and export an MP4 while preserving the source proportions. Free to use, with no sign-up required.
Files processed on your deviceFFmpeg runs locally in your browser. First use loads a roughly 32 MB same-origin WebAssembly core and can take time and use substantial memory. Combined inputs are limited to 100 MB, media duration to 30 minutes, frame dimensions to 4,096 pixels per side and 16 megapixels total, and output to 250 MB. Codec and filter support depends on the bundled build.
01 How it works
- Choose one video file.
- Set a width from 64 to 3,840 pixels.
- Download the resized MP4.
02 Good to know
Height is calculated to preserve the source aspect ratio. Output is re-encoded as MP4 and limited to 4,096 pixels per side and 16 megapixels total.
03Choose a width for video resizing
Choose a video and select 240p (426 pixels), 360p (640 pixels), 480p (854 pixels), 720p (1,280 pixels), or 1080p (1,920 pixels). The tool calculates the height from the source aspect ratio and exports an MP4.
The output must stay within 4,096 pixels on either side and 16 megapixels total. Very wide or tall sources can reach those bounds before the selected width.
04Limits and compatibility
FFmpeg runs in your browser and re-encodes the video. Combined inputs are limited to 100 MB and 30 minutes, and output is capped at 250 MB. Choose a width that fits the destination without exceeding the frame limits.
05 Questions
Does resizing change the aspect ratio?
The tool calculates the output height from the source aspect ratio to preserve the proportions.
Which output widths are available?
Choose 426, 640, 854, 1,280, or 1,920 pixels. Height follows the source aspect ratio, subject to the output dimension limits.