Crop, Trim, and Resize Videos Online
Choose a video to crop or resize
Drop a video here, or select one from your device.
Supports MP4, WebM, MKV, MOV, and AVI · Exports WebM · Your video stays on your device.About
Crop a video to a custom area or a common aspect ratio, trim unwanted time from the beginning or end, resize it to an exact output resolution, and save the result as a WebM file. MP4, WebM, MKV, MOV, and AVI files are supported. Processing happens locally in your browser—your video is never uploaded.
How to crop a video
- Select a video from your device or drag and drop it into the cropper.
- Drag inside the crop area to reposition it, then drag the handles to resize it.
- Drag the trim handles to select the part of the video to keep, or set either boundary to the playhead.
- Choose an aspect ratio such as 16:9, 1:1, 4:5, or 9:16.
- Keep the crop resolution, choose a long-edge preset, or enter a custom width and height.
- Select a frame rate and quality level, then choose Save Video.
The editor previews only the selected time range with the same crop. Exported dimensions are kept even for broad WebM codec compatibility.
MP4, MOV, WebM, and MKV exports use a sequential Mediabunny decode pipeline instead of seeking separately for every output frame. AVI and compatibility exports use the same Mediabunny WebM writer, so every export path shares one maintained output pipeline.
AVI support
Browsers cannot reliably preview AVI containers directly, so the tool uses a small demuxer hosted with this site to read AVI packets and sends them to WebCodecs one frame at a time. It does not convert the entire source into a temporary in-memory video, so large AVI files do not need to fit inside a WebAssembly heap. Motion JPEG AVI has a dedicated local decoder path.
AVI is a container and can hold many video and audio codecs. The tool supports AVI video tracks that the browser's WebCodecs implementation can decode, plus Motion JPEG. Supported AVI audio tracks—including common MP3 and PCM audio in current Chromium browsers—are decoded incrementally and saved as Opus. If the browser cannot decode a track's legacy codec, the editor identifies that limitation and exports video only.
Browser compatibility
Video export requires a browser with the WebCodecs VideoEncoder API. Preserving audio also requires the corresponding audio decoder and Opus encoder support. Recent Chromium-based browsers such as Chrome and Edge offer the broadest compatibility. The tool selects VP9 when available and falls back to VP8.
Frequently asked questions
Can I remove time from the beginning or end?
Yes. Move the start and end trim handles, enter exact times in seconds, or move the playhead and choose Set to playhead. Preview playback stays inside the selected range, and the exported video starts at time zero.
Can I crop a landscape video into a vertical video?
Yes. Choose Vertical · 9:16, move the selection over the important part of the frame, and select a suitable output resolution such as a 1080-pixel long edge.
Can I enter an exact video resolution?
Yes. Choose Custom under Output resolution, then enter the width and height. Keep the aspect ratio option enabled to avoid stretching.
What format does the tool export?
The tool exports a WebM file encoded with VP9 or VP8. Audio is encoded as Opus when it can be preserved.
Can I crop an AVI video?
Yes. Select the .avi file normally. The browser reads it incrementally and opens it in the same crop editor without first creating a full temporary copy. Compatibility depends on the video and audio codecs stored inside the AVI container.
Why can video export take a while?
Every frame must be decoded, cropped, resized, and encoded on your device. Longer videos, higher resolutions, and 60 fps exports require more processing.
Is there a file-size limit?
The tool does not impose an upload limit because the video is not uploaded. AVI input is read incrementally. When Chrome or Edge offers a save-file dialog, output is also written progressively to disk; the download fallback must hold the completed output in browser memory. Available storage, video duration, resolution, and device performance still set practical limits.