Crop video in your browser

How to crop a video

1. Drop your video onto the box above, or use Choose video. It opens straight from your device - nothing is sent anywhere.
2. Drag a box over the preview, or pick an aspect ratio such as 1:1 or 9:16 to start from a centred crop.
3. Move the box by dragging inside it, and resize it from the corners or edges. The exact pixel values are always shown, and you can type them instead.
4. Use Preview crop to watch just the selected area play back.
5. Choose the format, quality and whether to keep the audio, then press Crop & export.
6. Download the finished video.

Cropping is not resizing

These get confused constantly, and they do different things. Cropping throws away the parts of the picture outside your box: the output is smaller because you kept less of the frame, and what remains looks exactly as it did before. Resizing keeps the whole picture and scales it up or down.

This tool crops. The exported dimensions are the dimensions of the box you drew, and the footage inside it is never stretched or squashed to fit a shape it was not. If you need the whole frame at a different size, that is a resize, not a crop.

Aspect ratios, and why they matter

An aspect ratio is the shape of the frame - its width compared with its height. Most cameras record 16:9, a wide landscape rectangle. Phone-first feeds usually want 9:16, the same rectangle stood on its end, and square 1:1 still turns up in feeds and ad slots.

Choosing a preset gives you the largest box of that shape that fits your footage, centred, which you can then drag to the part of the picture you actually want to keep. Cropping a 16:9 video to 9:16 means most of the width is discarded, so it is worth checking that your subject is still inside the box before exporting. Freeform lets you draw any shape at all.

Portrait video and rotation

Phone footage is a common source of confusion: many phones record landscape pixels and add a rotation flag telling players to turn the picture upright. The numbers stored in the file therefore do not match what you see on screen.

The crop box here works on the frame as it actually appears - upright - and the export uses the same coordinates, so the region you select is the region you get. You do not need to know or care which way the pixels are stored.

Why the video never leaves your device

There is no upload endpoint behind this page. The file is opened through a local object URL, the crop preview is drawn from frames your browser has already decoded for playback, and the export runs in a Web Worker inside your own browser. The finished video is downloaded from your browser's memory.

That means no queue, no waiting for an upload, and no copy of your footage sitting on someone else's disk. It also means the work is done by your device, so a long or high-resolution video will take longer on a phone than on a desktop.

What people use it for

• Turning a landscape recording into a vertical clip for a phone-first feed.
• Cropping to square for a feed or an ad slot.
• Removing black bars, a stray window edge, or someone walking through the background.
• Tightening the framing on a screen recording so the important part fills the frame.
• Cropping personal or confidential footage without handing it to a stranger's server.

Limitations worth knowing

• Cropping always re-encodes, so it takes longer than a straight copy and is not quality-free.
• Exported dimensions are snapped to even numbers, because video encoders require it.
• Very large or long videos can exhaust browser memory, particularly on phones and older machines.
• Some codecs cannot be decoded or encoded by some browsers at all.
• Closing the tab during an export cancels it - the work happens in your browser, not on a server.

Questions

Is my video uploaded to your server?

No. The file is opened directly from your device, the crop preview is drawn from frames your own browser has already decoded, and the cropped video is created in your browser and saved straight from it. The video, its frames and the exported file never reach A2Z.Tools.

What is the difference between cropping and resizing?

Cropping cuts away the parts of the picture outside your selection, so the output is a smaller window onto the same footage and nothing is squashed. Resizing keeps the whole picture and scales it to different dimensions. This tool crops: the exported size is the size of the box you drew, and the video inside it is never stretched.

Does cropping reduce the quality?

Cropping always requires the video to be encoded again, because the frames themselves change size. That re-encode is not quality-free, though the High preset keeps it close to the source. There is no way to crop a compressed video without re-encoding it, so no tool can honestly call cropping lossless.

Can I crop a portrait video filmed on a phone?

Yes. Phone videos often store landscape pixels plus a rotation flag, so the numbers in the file do not match what you see. The crop box works on the frame the way it actually appears, upright, and the exported crop covers exactly the area you selected.

Which formats and browsers work?

MP4 and WebM are the most reliable. MOV, M4V, MKV and OGV often work too, but that depends on the codecs inside the file and on your browser rather than on the extension. Recent Chrome and Edge have the widest support. The tool checks what your browser can actually do with your file and says so if something is not possible.

Why are the exported dimensions slightly different from what I dragged?

Video encoders need even numbers of pixels, so the crop is snapped to the nearest even width, height and position. The tool shows the real exported dimensions next to the crop box, so the number you see is the number you get.

Need to shorten a clip rather than reshape it? Use the Video Cutter to trim a video to the section you want, also without uploading it.