Free · no signup · never uploaded
Crop Video
Cut the frame down to the part you actually want — in your browser, never uploaded.
Drop a video here or choose a file
or drop your file here.
MP4 · MOV · MKV — cropped in your browser, never uploaded
Runs in your browser — your file is never uploaded.
Short answer
To crop a video, drop it below, set the crop rectangle (width, height and offset in pixels) and download the result. It runs entirely in your browser with ffmpeg — nothing is uploaded. Cropping changes the frame, not the length.
Cropping vs. resizing — which do you want?
Cropping throws away the edges of the picture and keeps the pixels in the middle at their original size. Resizing keeps the whole picture and scales it. If you want to remove a black bar, a watermark in a corner, or dead space around your subject, you want cropping. If you want the same shot to be a smaller file or fit a smaller screen, you want resizing — which is what the compressor does as a side effect.
Getting to a square or vertical aspect ratio
Social platforms want specific shapes: 1:1 for a square post, 9:16 for a vertical story or short. To reach them from a normal 1920×1080 clip, crop to 1080×1080 for a square (offset x by 420 to centre it), or 608×1080 for 9:16. The tool reports your clip’s real dimensions once it loads, so you can work out the offsets from actual numbers rather than guessing.
Video formats to MP4 — what happens to your file
| Input format | Usual codecs inside | Conversion | Max file size |
|---|---|---|---|
| MOV (QuickTime) | H.264 + AAC | Rewrap (lossless) | 500 MB |
| MKV (Matroska) | H.264 + AAC | Rewrap (lossless) | 500 MB |
| WebM | VP8/VP9 + Opus | Re-encode to H.264 | 100 MB |
| AVI | MPEG-4/DivX | Re-encode to H.264 | 100 MB |
| GIF | Animated GIF | Re-encode to H.264 | 200 MB |
A rewrap copies the existing video and audio streams into an MP4 container untouched — it is lossless and finishes in seconds. A re-encode decodes and re-compresses, so it takes longer and loses a little quality. Size caps differ because everything runs on one thread in your browser.
How the crop works
Everything happens locally in your browser with ffmpeg — here is exactly how:
- Load the engine. ffmpeg compiled to WebAssembly loads once from this site — your file is never uploaded.
- Read the dimensions. your browser decodes the clip’s metadata locally to report its true width and height, so the crop rectangle can be checked against the real frame.
- Apply the crop filter. ffmpeg’s crop=w:h:x:y filter selects the rectangle you specified and discards the rest of each frame.
- Re-encode and return. the cropped frames are encoded with libx264 (veryfast, single thread) and AAC audio into an MP4 you can download.
Assumptions
- Everything runs client-side; speed depends on your device and the clip length.
- The crop rectangle must fit inside the original frame.
- Cropping re-encodes the video, so a small amount of generational quality loss is unavoidable.
Last reviewed: July 19, 2026
Frequently asked questions
How do I crop a video?+
Drop your video in above, enter the width, height and the x/y offset of the area you want to keep, then download the result. It all happens in your browser — nothing is uploaded.
Are my videos uploaded to a server?+
No. Everything runs 100% in your browser using ffmpeg compiled to WebAssembly, so your file never leaves your device. Nothing is uploaded, stored, or sent anywhere — and once the converter has loaded it even works offline.
What do x and y mean?+
They’re the position of the crop rectangle’s top-left corner, measured in pixels from the top-left of the original frame. x=0, y=0 keeps the top-left; increasing x moves the rectangle right, increasing y moves it down.
Does cropping reduce quality?+
Cropping has to re-encode the video, so there is some generational loss — but the tool encodes at a high-quality setting, so it is normally not visible. The result is smaller simply because there are fewer pixels per frame.
Why is the first conversion slower?+
The first time, your browser downloads the ffmpeg engine (about 31 MB) and starts it up. That happens once — later conversions reuse the loaded engine and are much faster.
Does cropping make the video shorter?+
No. Cropping only changes the frame — every second of the clip is kept. To shorten a video, use the trim tool instead.
Related tools
Video is processed entirely in your browser with ffmpeg and never uploaded.