How to resize a video
- Drop an MP4, MOV, M4V, WebM or MKV into the box above.
- Pick a size: 1080p, 720p, 480p, 360p, Half, or Custom to type a width and height.
- Read the line under the options: it gives the exact new size, the bitrate, and roughly how big the file will be. Choose Smaller file or Higher quality if you want to move that number.
- Press Resize video, check the result in the player and download it.
What each size gives you
| Choice | Landscape 1920×1080 becomes | Vertical 1080×1920 becomes |
|---|---|---|
| 720p | 1280×720 | 720×1280 |
| 480p | 854×480 (853.3 rounded to even) | 480×854 |
| 360p | 640×360 | 360×640 |
| Half | 960×540 | 540×960 |
The p number is always the short side, so a phone video filmed upright stays upright. Phones store vertical video on its side with a note saying how to turn it; the page applies that note first, so the width and height you see are the ones you get.
Smaller picture, smaller file? Only if the bitrate drops too
Most people resize a video because the file is too big. A video encoder, though, spends whatever bitrate it is given, whatever the picture size. We re-encoded the same 1080p phone clip with FFmpeg (23 October 2026):
| Size | Original bitrate kept | Quality-based (CRF 23) |
|---|---|---|
| 1080p | 12.30 MB | 16.55 MB |
| 720p | 12.23 MB (−0.5%) | 9.31 MB (−44%) |
| 480p | 12.17 MB (−1%) | 4.40 MB (−73%) |
Keeping the original bitrate made the 480p file practically the same size as the 1080p one. With a quality target, 720p needed about 56% of the 1080p size and 480p about 27%. That is roughly the pixel ratio raised to the power 0.75 (0.54 and 0.30): smaller pictures need a little more data per pixel. This page uses that rule to set the bitrate, so the size it predicts is close to what you get. If you need a file under an exact limit, such as 25 MB for an email, Compress video works from the target size instead.
Why sizes are always even numbers
H.264, the format that plays everywhere, needs even widths and heights. The usual FFmpeg recipe,
-vf scale=720:-1, turns a 1920×1080 video into 720×405 and then stops with
“height not divisible by 2”; a vertical video fails the same way with “width not divisible by
2”. (FFmpeg’s fix is -2 instead of -1.) This page rounds to the nearest even
number and tells you when it did, so you never get the error or a silently stretched picture.
Changing the shape
With Custom and Keep proportions unticked, you can make a 16:9 video square or vertical. You then choose what happens to the difference: black bars keep the whole picture, fill the frame cuts equal amounts off both edges, and stretch distorts it. To choose which part is kept, for example a person on the left, use Crop video and then resize the result.
Quality and privacy
Resizing has to re-encode the picture; the sound is copied without change where the format allows. Shrinking looks clean. Enlarging a small video makes it bigger but adds no detail, and the page warns you when you are doing that. Everything runs in your browser with WebCodecs: the video is not uploaded, there is no watermark and no account.