OneTaskBy Tim King · Updated
Video Resizer
Resize a Video to 1080p, 720p or 480p, Keeping the Aspect Ratio
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How the Video Resizer works
This video resizer scales a clip to a standard height such as 1080p, 720p or 480p and keeps its shape. Drop in a video, pick a height, press Render and download the smaller file. The work happens in your browser, so the video is never uploaded.
Phones now record 4K by default, and a minute of 4K footage can pass 350 MB. That is far more than an email attachment, a chat app or a quick upload over hotel Wi-Fi will cope with. Scaling down to 1080p or 720p is the quickest way to shrink a file while keeping it watchable.
How the video resizer works
Your browser plays the clip and draws every frame onto a canvas of the new size, then records that canvas with the MediaRecorder API. The width is worked out from the height you choose and the source's own aspect ratio, so a 16:9 clip stays 16:9 and a vertical 9:16 phone video stays vertical. Both sides are rounded to even numbers, because most video encoders require them.
The bitrate scales with the picture: about 3 bits per pixel per second, with a floor of 0.5 Mbit/s. That gives roughly 2.8 Mbit/s at 720p and 6.2 Mbit/s at 1080p, close to what YouTube and Vimeo use for their own streams.
Standard video resolutions
"720p" names the height. The width depends on the shape of the picture.
| Name | 16:9 landscape | 9:16 vertical | 4:3 |
|---|---|---|---|
| 2160p (4K UHD) | 3840 × 2160 | 1216 × 2160 | 2880 × 2160 |
| 1440p (QHD) | 2560 × 1440 | 810 × 1440 | 1920 × 1440 |
| 1080p (Full HD) | 1920 × 1080 | 608 × 1080 | 1440 × 1080 |
| 720p (HD) | 1280 × 720 | 406 × 720 | 960 × 720 |
| 480p (SD) | 854 × 480 | 270 × 480 | 640 × 480 |
| 360p | 640 × 360 | 202 × 360 | 480 × 360 |
| 240p | 426 × 240 | 136 × 240 | 320 × 240 |
For a vertical video, the "height" is the long side. Choose 1920 if you want a vertical clip 1080 pixels wide; 1080 gives a narrow 608-pixel-wide picture.
Which size to choose
- 1080p for anything that will be watched full screen on a laptop or TV.
- 720p for chat apps, email and support tickets. It looks sharp on a phone and is about half the data of 1080p.
- 480p or 360p for previews, slow connections and archive copies where size matters most.
Tips and pitfalls
Upscaling adds no detail. Picking a height above the source makes the file bigger but the picture is no sharper. The tool tells you when this happens.
The render runs in real time. A 3-minute clip takes about 3 minutes; trim first if you only need part of it.
Need an exact size limit? Pair this with the video bitrate calculator to see what resolution and length fit under a platform's cap.
How to read the result
The stats show the source resolution and file size, the new resolution, and the new file size. Play the result to check it, then Download.
To hit a file size in megabytes rather than a frame size, use the video compressor.
FAQ
Does resizing a video reduce its file size?
Usually a lot. Halving the height cuts the pixel count to a quarter, and this tool lowers the bitrate with it. A 4K phone clip resized to 720p often ends up a tenth of its original size.
Will the video be stretched?
No. Only the height is chosen; the width follows the source's aspect ratio. To change the shape, use the video cropper or the square and story padder instead.
Is my video uploaded?
No. The resize is done by your browser's own video decoder and recorder on your device. Nothing is sent to a server, so private recordings stay private.
What format does the resized video use?
Chrome, Edge and Firefox record WebM with VP9 or VP8 video. Safari records MP4 with H.264. Open this page in Safari if a platform will only accept MP4 files.
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