Resolution is the number of pixels in each frame, and many places care about it: an editor that struggles with 4K, a website player sized for 720p, a social network that wants 1080 by 1920 for vertical clips, or a client who asked for exact dimensions. Resizing changes those pixels while keeping the content, timing and sound of the video.
This tool scales MP4, MOV, WebM, MKV and AVI files to 1080p, 720p or 480p, or to a custom width and height. A Fit setting decides what happens when the shape of the video and the shape of the target differ. Files are processed one after another in your browser, and each result keeps its original container.
Presets, custom sizes and aspect ratio
The presets describe the short side of the picture, the way video resolutions are usually named. 720p means a frame of 1280 by 720 pixels for a landscape video and 720 by 1280 for a portrait one; the tool turns the frame to match each clip, so a phone video filmed upright stays upright. 1080p uses 1920 by 1080 and 480p uses 854 by 480. Custom takes any width and height from 16 to 7,680 pixels, used exactly as typed; odd numbers are rounded down to even ones, which the H.264 encoder requires.
When the video's proportions differ from the target's, something has to give. Fit inside scales the whole picture until it touches the frame, so nothing is cut, but one side can come out shorter than the target: a 4:3 clip at the 720p preset becomes 960 by 720. Fill and crop scales the picture until it covers the frame completely and trims what overflows, equally from both sides, so the result has exactly the requested size. Neither option stretches or squashes the picture.
When to resize rather than compress or crop
Making 4K footage easier to edit and share
Bringing a 4K clip down to 1080p quarters the number of pixels, so it plays smoothly in older editors and on modest laptops while still looking sharp on most screens.
Meeting a platform's exact dimensions
For a square post choose Custom with 1080 by 1080 and Fill and crop; for vertical Reels, Shorts or TikTok use 1080 by 1920. The centre of the picture is kept.
Matching clips before combining them
Resizing several clips to the same resolution makes them consistent for a presentation or a video editor that expects one size throughout.
What the resize does to quality and format
Changing the frame size means decoding every frame, scaling it and encoding it again, so the whole file is re-encoded. MP4, MOV and MKV files come out as H.264 video with AAC sound, WebM as VP8 with Vorbis, and AVI as MPEG-4 Part 2 with MP3 sound, all at a balanced quality setting. The file name gets the new size added, such as -720p or -1080x1920, so it never overwrites the source.
Scaling down is where resizing shines: detail is averaged, so the result looks clean and is usually much smaller. Scaling up is possible, because a preset or custom size larger than the source is honoured, but no new detail is invented; the picture is only spread over more pixels and the file grows. The work is done by ffmpeg built for WebAssembly, which your browser downloads once (about 31 MB) and keeps. It uses one processor thread, so long or high-resolution clips take a while, and files can be up to 500 MB.
Bu araç nasıl kullanılır
- Drop one or more videos on the box above, or click it to browse. MP4, MOV, WebM, MKV and AVI are accepted.
- Choose a Size: 1080p, 720p, 480p, or Custom and enter Width and Height in pixels.
- Pick a Fit: Fit inside to keep the whole picture, or Fill and crop to get exactly that size.
- Press Convert, then download each resized video or all of them with Download all (.zip).
Limitations
- Every resize re-encodes the video, which takes time and adds a small generation of compression.
- Fit inside never adds black bars, so the result can be narrower or shorter than the size you chose. Use Fill and crop for an exact frame.
- Fill and crop always keeps the centre. To choose which part of the frame stays, use Crop Video first.
- Upscaling makes a bigger file without making it sharper.