Video Cropper

Crop video dimensions to remove unwanted areas with aspect ratio presets.

Tested tool guide Tested browser tools Checked August 16, 2026

What Video Cropper does, with a checked example

Video Cropper cuts a video down to a rectangle you choose: load a file, position a crop box over a preview frame, pick an aspect ratio preset, and download a new video containing only that region. The crop is applied by decoding the source and encoding the selected region into a fresh file. What people most often get wrong: cropping never adds picture. A 16:9 source cannot become a tall 9:16 frame without throwing away most of its width, and the result is a new encode, so quality and file size come from the encoder, not from how much you removed.

Worked example

A concrete input and expected output from the current implementation.

Input

1920x1080 video, crop with the 1:1 (square) preset, region centered on the frame.

Expected output

A 1080x1080 video of the same duration, containing the central square of every frame. The output is 840 pixels narrower: the preset centers the box, so 420 pixels are cut from each side (1920 - 1080 = 840, divided equally).

1:1 fixes output width equal to height, and the crop box is bounded by the source, so the largest possible square is 1080x1080. Centering splits the removed width evenly between the left and right edges, and duration is untouched because cropping only changes dimensions.

How the result is produced

Crop box and presets

The source is decoded and shown as a preview, and a crop rectangle sits over it. Dragging moves the rectangle; its handles resize it, and the preview dims everything outside it. Choosing a preset locks the rectangle to that aspect ratio so width and height scale together, and the rectangle is clamped to the source frame, which sets the largest output it can produce.

Re-encode and export

Export reads only the pixels inside the rectangle, from every frame, and writes them into a new video at the crop dimensions. The picture is re-encoded, so the output's bitrate and quality follow the export settings; audio and duration pass through as-is. Processing time scales with duration and resolution, and longer or higher-resolution sources take correspondingly longer.

Good uses

Cutting letterbox or pillarbox bars out of a screen recording or a video of a 4:3 presentation so the file contains only the picture.
Producing a 9:16 clip from a 16:9 source for stories or vertical reels, centering the subject before export.
Removing a fixed distraction at the frame edge, such as a watermark, ticker, or timestamp, without changing the timeline.

Limits and checks

The crop box cannot exceed the source, so the output resolution is always smaller than or equal to the source. Cropping a 1920x1080 video to 9:16 leaves only a strip about 608 pixels wide (1080 x 9/16), roughly a third of the frame.
File size is decided by the new encode, not by the area removed. The same crop exported at different bitrates can differ in size by several times, and a high-bitrate export can come out larger than the original file.
Cropping changes frame dimensions only. Duration, frame rate, and audio are unchanged, and if black bars are already part of the recorded picture, removing them changes the container ratio but not the picture's own ratio - a 16:9 picture letterboxed inside a 4:3 frame stays 16:9 after the bars are cut away.

Common questions

Will the cropped video be smaller than the original?

Not automatically. The output is encoded fresh, so its size tracks the export bitrate and the content of the region, not the area removed. A calm scene cropped tightly can come out very small; a busy scene exported at a high bitrate can exceed the original. Treat size as a result of the export settings, and check them before downloading.

Is my video uploaded while it is processed?

No. The file is decoded and re-encoded inside your browser on this page, so the video itself does not leave your machine. The trade-off is that speed depends on your hardware: a long or high-resolution source takes noticeable time, and very large files can strain your browser's memory.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.