Will resizing make the file smaller?

Nearly always, because the bitrate is set from the new dimensions. Going from 1080p to 720p usually lands around a third of the original size, with the exact figure shown before you start.

How do I make a square video for Instagram?

Type the same number in width and height, 1080 by 1080 for instance, and set the shape option to fill and crop. That keeps the frame full and trims the sides rather than adding bars.

Can I make a video larger?

No. Asking for more than the original has gives you the original size back. Enlarging invents pixels, which makes the file bigger without making the picture better, and the tools that do it well are not browser tools.

Why is my height one pixel different from what I typed?

Because it was odd. H.264 stores colour at half resolution horizontally and vertically, so both dimensions have to be even, and an odd number is rounded up by one.

Resize Video

Scales a video to a resolution you pick, or to exact dimensions. The presets go by the shorter side, so 720p means the same amount of detail whether the clip is landscape or came off a phone held upright.

Choose a video or drop it hereMP4, MOV, WebM or MKV, up to 500 MB.

Runs entirely in your browser. Your files are never uploaded.

How to use Resize Video

1Choose a video, or drag it onto the box.
2Pick a preset, or type a width and a height.
3Choose what should happen if the new shape differs from the old one.
4Resize, then download.

What a resolution name means on a portrait clip

720p is the height of a landscape picture, and the name stops making sense the moment the video is taller than it is wide. Capping the height of a 1080 by 1920 phone clip at 720 would leave it 406 by 720, which is a quarter of the pixels anyone asking for 720p had in mind.

So the presets here cap the shorter side. A landscape 1080p video becomes 1280 by 720 and a portrait one becomes 720 by 1280, which is what phones and social apps both mean by 720p. Typing a width and a height gives you exact control when a platform wants a specific size.

Sizes above the original are left alone. Enlarging a video adds bytes and no detail, and someone picking 1080p for a 480p file is not asking for a bigger file that looks the same.

When the shape changes

Asking a 16:9 video for a square or a vertical frame means the two shapes no longer match, and something has to give. Fitting inside keeps the whole picture and leaves bars. Filling and cropping keeps the frame full and loses the edges, which is what a vertical cut of a landscape interview usually wants. Stretching keeps everything and distorts it, and is almost never what anyone wants.

Both dimensions end up even numbers, because H.264 stores colour at half resolution in each direction and an odd number of pixels has nowhere to put the last half. An encoder refuses an odd width outright, so a typed 1081 becomes 1082.

The bitrate follows the size

A smaller picture needs fewer bits, and the figure is set from the new dimensions rather than carried over from the original. Keeping a 1080p bitrate on a 480p picture wastes most of it; using a 480p bitrate on a 1080p picture leaves it smeared.

The scaling is not proportional to the pixel count. A small frame needs more bits for each of its pixels than a large one, because its detail is denser relative to its size, which is why the figure for 360p is higher than a straight division would suggest.

Limits

500 MB per file.
The result is an MP4 with H.264 video.
Sizes larger than the original are ignored, since upscaling adds no detail.
Both sides are rounded to even numbers, which H.264 requires.
Resizing re-encodes, so it takes real time: 20 seconds of 720p down to 480p took 1.6 seconds in testing.

Frequently asked questions

Will resizing make the file smaller?: Nearly always, because the bitrate is set from the new dimensions. Going from 1080p to 720p usually lands around a third of the original size, with the exact figure shown before you start.
How do I make a square video for Instagram?: Type the same number in width and height, 1080 by 1080 for instance, and set the shape option to fill and crop. That keeps the frame full and trims the sides rather than adding bars.
Can I make a video larger?: No. Asking for more than the original has gives you the original size back. Enlarging invents pixels, which makes the file bigger without making the picture better, and the tools that do it well are not browser tools.
Why is my height one pixel different from what I typed?: Because it was odd. H.264 stores colour at half resolution horizontally and vertically, so both dimensions have to be even, and an odd number is rounded up by one.