Match the destination, not the source master
A camera or screen recording may be much larger than the place where it will be watched. Choose the largest dimensions that the destination actually needs rather than preserving unnecessary pixels.
Resize Video
Change video dimensions while preserving aspect ratio.
Smart workspace
Prepare your video file
Server processing · up to 50 MB per file. Worker availability is checked before upload.
1 file per jobChecking processor…
Output & controls
How the new size is applied
Enter a width and a height and the video is scaled to fit inside that box with its proportions kept, then re-encoded as an H.264 MP4 (CRF 28, veryfast preset) with AAC audio. Both sides are rounded to even numbers, which H.264 players expect.
| Source | Box entered | Result |
|---|---|---|
| 1920 × 1080 landscape, 20 s, 15.71 MB | 1280 × 720 | 1280 × 720, 1.81 MB |
| 1080 × 1920 portrait, 10 s, 8.60 MB | 1280 × 720 | 406 × 720, 0.41 MB |
| 1080 × 1920 portrait, 10 s, 8.60 MB | 720 × 1280 | 720 × 1280, 0.99 MB |
| 1440 × 1080 (4:3), 5 s | 1920 × 1080 | 1440 × 1080, no stretching |
| 640 × 360, 3 s | 1280 × 720 | 1280 × 720, enlarged |
- Turn the box around for portrait clips. Typing 1280 × 720 for a vertical phone video gives a result only 406 pixels wide; enter 720 × 1280 to get portrait 720p.
- Odd results are rounded to an even width or height: fitting a 1080 × 1920 clip into a 1280 × 720 box gives exactly 405 pixels of width, which becomes 406 so the H.264 encoder accepts the frame.
- The picture is never stretched. A 4:3 video in a 1920 × 1080 box stays 1440 × 1080; this tool adds no black bars and does not crop.
- Small videos are enlarged to fill the box. Upscaling adds pixels, not detail, and makes the file larger, so enter the source size or smaller.
- The re-encode shrinks files on its own: our 1080p test fell from 15.71 MB to 1.81 MB at 1280 × 720. CRF 28 is softer than a phone’s own encoding, so small text in screen recordings can blur.
- MOV, MKV, AVI and WebM inputs all come back as MP4, and the audio is re-encoded to AAC at about 128 kbps.
If the goal is a smaller file at the same dimensions, use the Video Compressor; if you need exact dimensions with bars or a crop, use a video editor.
Measured on 2026-10-19 by running this tool’s FFmpeg command (scale with force_original_aspect_ratio=decrease, libx264 CRF 28) on synthetic test clips, not on user uploads.
How to use Resize Video
- 1. Choose a supported MP4 or MOV or MKV or AVI or WEBM source file.
- 2. Set the options for the MP4 result and its destination.
- 3. Run Resize Video and wait for processing to finish.
- 4. Open the result, verify playback or contents, then download the copy.
Input, output and processing
Input: MP4, MOV, MKV, AVI, WEBM · Output: MP4.
Heavy processing uses the dedicated media worker instead of blocking the web request. Keep the source until you have checked the generated result.
Practical guide
What to know before you process this file
Resize video when the destination needs different pixel dimensions; keep the aspect ratio unless the destination explicitly requires a different shape.
Best for
Phone and social uploads
Best for
Web embeds
Best for
Reducing oversized source dimensions
Protect the aspect ratio
Locking the original ratio prevents stretched faces, circles and logos. If a destination needs a different shape, crop or add padding deliberately rather than distorting the frame.
Use compression for the remaining size problem
Two videos with identical dimensions can have very different file sizes because their codecs and bitrate differ. Resize for dimensions and compress for encoded size.
Questions people usually have
Does resizing a video reduce quality?
Downscaling removes some pixel detail. Upscaling increases dimensions but cannot recreate detail that was absent from the source.
What resolution should I use?
Use the destination requirement or the largest size you actually need for viewing. Avoid exporting a much larger frame than the destination can display.
Is video resolution the same as video quality?
No. Resolution is pixel dimensions. Quality also depends on bitrate, codec, frame rate, source quality and the content itself.
Resize video to the dimensions your destination can use
A good video size depends on where it will be watched. Resize Video is for changing the pixel dimensions without treating every upload as if it needed the largest possible frame.
Preserve the shape when the content matters
Keeping the aspect ratio avoids stretched faces, circles and logos. Unlock exact width and height only when the destination explicitly requires a different shape.
Resolution and file size are related, but they are not the same thing. Two videos at the same dimensions can still have very different sizes.
Pick the target before exporting
Use a destination-sized preview where possible, then check text and fine details at normal playback. If the file is still too large, compression is the next step rather than repeatedly resizing.
Useful next steps
Choose the next operation that matches what you need to do with the file.
Frequently asked questions
Does resizing a video reduce quality?
Downscaling can remove detail, while upscaling cannot recreate detail that was not present in the source. Keep the original when quality matters.
What resolution should I choose?
Choose the resolution required by the destination or the largest size you actually need. Avoid exporting much larger than the viewing context demands.
Can I resize without changing the aspect ratio?
Yes. Keep the aspect ratio locked when the destination does not require a fixed shape.
Is resizing the same as compression?
No. Resizing changes dimensions. Compression changes how efficiently the media is encoded. They can be used together.
Related video tools
Change Video Resolution
Convert video to a practical resolution preset.
Trim Video
Cut a video to the exact section you need.
Video Compressor
Reduce video file size with controlled quality settings.
AVI to MP4 Converter
Convert AVI videos to MP4 for modern playback.
Change Video Speed
Speed up or slow down video playback with audio handling.
MKV to MP4 Converter
Convert MKV videos to MP4.