Crop Video

Crop a video to 9:16, 1:1 or 16:9 in your browser and turn landscape footage vertical for Shorts, Reels and TikTok. Free, private, no upload.

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Drop your file here (.mp4, .mov, .m4v, .webm)

🔒 Private by design: your files are processed locally in your browser and never uploaded to any server.

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The centred rectangle the crop filter receives

Cropping is a geometry problem before it is a video problem. The tool runs FFmpeg over your file once with no output, reads the pixel dimensions out of the stream dump, and from those two numbers plus your chosen ratio it computes a single rectangle: a width, a height, and an x and y offset from the top left corner.

The rule it follows is the largest rectangle at your target ratio that fits inside the source. Compare the source’s own width-to-height ratio against the target. If the source is proportionally wider, the full height is kept and the width is trimmed from both sides. If it is proportionally taller, the full width is kept and the height is trimmed from top and bottom. Whichever edge is the surplus one loses the same amount at each end, which is what keeps the result centred.

Both sides are then rounded down to even numbers, because H.264 rejects odd frame dimensions outright, and the offsets are recalculated from that final size so the rectangle stays centred and never overruns the source. Those four numbers go straight into FFmpeg’s crop filter and nothing else about the framing is negotiable.

Producing the cropped MP4

  1. Drop your video into the box above, or click Choose a file. MP4, MOV, M4V and WEBM are accepted.
  2. Set Crop to. Vertical (9:16) for Shorts, Reels, TikTok is the default, with Square (1:1) for feed posts and Widescreen (16:9) for YouTube, landscape as the alternatives.
  3. Click Crop Video. The dimensions are read first, then the crop and the encode run as a single FFmpeg pass.
  4. Download the file. It keeps your original name with -crop-9x16, -crop-1x1 or -crop-16x9 added and an .mp4 extension.

A 1920x1080 clip cropped to 9:16 keeps 608 pixels of width

The numbers are worth seeing before you commit footage to this. Take standard 1080p, 1920 by 1080. Nine-sixteenths of 1080 is 607.5, which rounds to 608 and is already even, so the output frame is 608 by 1080 and the rectangle starts 656 pixels in from the left edge. Two thirds of your image width is gone, permanently.

Square is gentler on the same source: 1080 by 1080, starting 420 pixels in. Going the other way, a portrait 1080 by 1920 phone clip cropped to widescreen gives 1080 by 608, discarding 1312 pixels of height.

None of that is a flaw in the tool, it is simply what changing aspect ratio by cropping means. It also explains why the result is often softer than expected on a platform that expects a tall frame: 608 pixels of width upscaled to fill a modern phone screen has less to work with than the 1080 the platform was hoping for. Starting from higher resolution footage is the only real fix. Aspect Ratio Calculator will work the target dimensions out for you beforehand, and Resize Video is the page to use when the target is a named platform frame rather than a crop, since it standardises the output to a fixed resolution at the ratio you pick and can pad with bars instead of trimming anything away.

CRF 20, AAC audio and the re-encode you cannot skip

Some video edits are free. Rotating a clip can be a metadata flag, and trimming on keyframe boundaries can be a packet copy, which is why Trim Video and Rotate Video can finish almost instantly on a long file. Cropping is not in that family: every frame’s pixels are physically different afterwards, so every frame has to be decoded, filtered and encoded again.

The encode uses libx264 at CRF 20 with the fast preset. CRF 20 is a quality-leaning number rather than a size-leaning one, on the reasoning that you came here to reframe a video and not to compress it. It is still lossy compression, and why re-encoding loses quality sets out what that actually costs on a second generation. The output also carries the faststart flag, so its index sits at the front of the file and a browser or an upload form can read the duration immediately.

Audio follows the source. When the probe finds an audio stream, it is re-encoded to AAC at 128 kbps; when it does not, the encode passes -an and produces a genuinely silent file rather than an empty track.

When the subject sits off to one side

The honest limitation of a centred crop is that it assumes your subject is centred too. An interview shot with the guest framed on the right, a gameplay capture with the minimap in a corner, a webinar recording with slides on one side and a webcam thumbnail on the other: a 9:16 crop of any of those will take the middle and leave the interesting part outside the frame.

There is no repositioning control here, so the practical workflow is to look at the download before you upload it anywhere. If the framing is wrong, the alternatives are re-shooting, editing in a desktop tool that offers a movable crop box, or choosing a less aggressive ratio such as 1:1 that discards less. The rest of the collection, including the tools that pair well with this one, is on the video tools hub.

Frequently asked questions

Can I drag a box to choose which part of the frame survives?

No. The rectangle is always centred, and whichever edge is proportionally too long is trimmed equally from both sides. That suits a talking head or a product demo shot in the middle of frame, and it will cut into a subject who stands to one side, so preview the download before you publish it.

My source is already 9:16 and I picked 9:16. Does it just pass through?

The crop rectangle ends up covering the whole frame, but the file is still fully decoded and re-encoded, because the tool has no pass-through shortcut. You get a valid MP4 that is one encoding generation further from the original with nothing gained, so there is no reason to run a clip through at its existing ratio.

Why is the width an even number like 608 rather than 607?

H.264 refuses odd frame dimensions, so both sides of the rectangle are rounded down to an even number after the ratio maths, and the offsets are recomputed from the final size so the crop stays centred and never runs past the source edges. That is where the odd-looking pixel counts come from.

I recorded on a phone and the crop landed somewhere unexpected. What happened?

The rectangle is computed from the width and height printed in the stream dump, and no rotation side data is consulted. Phone footage is often stored in one orientation with a rotation tag telling players to turn it, so the numbers the tool reads may not describe the frame you see in your player. Rotating the clip first only helps if you pick the rotate page's re-encode method, since its recommended fast method just rewrites the same rotation tag this page ignores and leaves the stored dimensions alone. That page also accepts MP4, MOV and M4V only, so a WEBM has to be converted before the route is open at all.

What happens to the audio?

If the clip has an audio stream it is re-encoded to AAC at 128 kbps, even when it was already AAC at a higher bitrate. If the clip has no audio stream at all, which is common with screen recordings, the encode passes -an and the output is silent rather than carrying an empty track.

Does the output keep my original container?

No, everything comes back as MP4 whether you fed in MOV, M4V or WebM, since the re-encode is happening anyway and MP4 plays in the most places. The filename gets a suffix naming the ratio, so a source called clip.mov becomes clip-crop-9x16.mp4.

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