Video Resizer

What Video Resizer does

Video Resizer is the video tool for dimensions: it sets a new width and height in pixels and saves the scaled clip as an H.264 MP4. Color edits, format changes, and compression-only jobs belong to Video Color Changer, Video Converter, and Video Optimizer.

Its strength is plain scaling with the aspect ratio locked by default, so you type a width and the height follows. Unlock it to force an exact size; the picture is then stretched to fit rather than cropped or padded with bars.

How to use it

1. Select Choose File and pick a video. Once it loads, Width and Height are filled in with its own size, also shown as Input dimensions under the preview.
2. Enter the target width in Width (px). While Lock Aspect Ratio is checked, Height (px) is disabled and calculated for you.
3. To set both values yourself, uncheck Lock Aspect Ratio and enter a height.
4. Select Render Preview. When it finishes, Output Preview shows the result with its Output size and Output dimensions.
5. Select Download Video to save it.

Formats and limits

• Input: common video files such as MP4, MOV, WEBM, MKV, and AVI, as long as the built-in FFmpeg decoder supports their codec.
• Output: MP4 with H.264 video at a fixed CRF of 23 and AAC audio at 128 kbps. The name ends with the new width, such as -1280w.mp4, or with both sides when the ratio is unlocked.
• Each side must be at least 16 pixels and is rounded up to an even number, which H.264 needs. There is no upper limit, but scaling up adds no real detail and makes rendering slower.

Settings explained

Width (px)

The output width in pixels, bumped to an even number on render.

Height (px)

Editable only when the ratio is unlocked. While locked, it is worked out from the source proportions and rounded to an even number.

Lock Aspect Ratio

On by default. Turn it off only when the target size must be exact, knowing the picture will look squeezed or stretched if the proportions differ from the source.

Further reading

• Make a video small enough to send - Choose between trimming, resizing, and compression, then check the downloaded video in its destination.

Privacy

Scaling is done by an FFmpeg build running in this tab. The tool loads that engine on first use from the jsDelivr CDN, or from this site if the CDN cannot be reached, and sends nothing back, so your source clip and the resized copy never leave the device. Selecting Clear releases both from memory.

FAQ

Why did my width change by one pixel?

H.264 needs even dimensions, so odd widths and heights are rounded up before encoding.

Can I turn a landscape video into a vertical one?

Not cleanly. With the lock on, the shape stays the same, and with it off the picture is distorted. This tool has no crop option.

Will a smaller size reduce the file size?

Usually, since there are fewer pixels to encode. For more control over compression, run the result through Video Optimizer.

Can I resize an animated GIF here?

This tool reads video files and always writes MP4. For animated GIFs, use GIF Resizer so the result stays a GIF.

Related tools

• Video Optimizer - shrink the file without changing its dimensions.
• Video Cropper - cut to an aspect ratio instead of scaling.
• Video Converter - switch to WebM or another codec.
• GIF Resizer - change the size of an animated GIF.
• Image Resizer - resize still images.