Crop a video to a square

Cut a video to a square, vertical or widescreen shape, taken from the middle of the frame. The sound stays and nothing is uploaded.

Drop your files here

.mp4, .mov, .mkv, .webm, .avi · up to 200 MB

Choose files

How to Crop the video

1
Add your video
MP4, MOV, MKV or WebM, up to 200 MB and five minutes. An AVI does not open here, so turn it into an MP4 with AVI to MP4 first. The clip appears in a player.
2
Pick the shape
Under “Shape of the crop”, pick 1:1, 4:5, 9:16, 16:9 or 4:3. A dashed frame marks the largest box of that shape in the middle of the picture, and it cannot be moved. Free cuts nothing.
3
Press Build video and download
The result is an MP4 of just that box, at the clip's own resolution and the same length, with the sound kept.

The square comes from the middle

Add a clip, and 1:1 is already selected under “Shape of the crop”. A dashed frame marks the largest square in the middle of the picture and dims the rest. Its side is the clip's short side, so a 1920 × 1080 clip gives 1080 × 1080. That cuts 420 pixels off the left and 420 off the right, 44 percent of the width. A vertical 1080 × 1920 clip loses the same share at the top and bottom. The frame cannot be dragged on this page, so the cut always keeps the middle.

Size, weight and time in our check

We tried 30-second test clips on October 21, 2026. A 1920 × 1080 clip of 46 MB became a 1080 × 1080 MP4 of 28 MB. A vertical 1080 × 1920 one went from 45 MB to 23 MB. Each took 3 to 5 seconds after “Build video” in Chrome on a 2023 Mac. The length, 30 frames a second and the stereo sound came through. The square keeps the clip's own pixels and is never enlarged. A 10-second 4K clip gave 2160 × 2160 in about 4 seconds, and a 1280 × 720 one gave 720 × 720. The bitrate shrinks with the picture. Each 16:9 clip kept 56 percent of its pixels and 52 to 62 percent of its weight.

Phone clips, square clips and file types

Phones can store a vertical video sideways, with a flag that tells the player to turn it. Our test clip stored this way showed upright, as 1080 × 1920, with the frame across its middle. The square came out upright too, with no flag left in the file. An already square clip is not left alone: the frame covers all of it, and the page encodes it again. Our square test clip came back at the same 1080 × 1080 and slightly heavier: 8.1 MB from 7.8 MB. MP4, MOV, MKV and WebM open here, up to 200 MB and five minutes. An AVI does not, so turn it into an MP4 with AVI to MP4 first.

When the subject is not in the middle

This works when the subject sits in the middle of the shot. Near an edge, the square can cut it off, and this page cannot move the frame. To keep everything in the shot, use Change Aspect Ratio instead. Its square holds the whole frame, with a blurred copy of the video or a flat colour around it. Here, the video is cropped in the browser tab and never leaves your device. The square is named after the original: holiday.mov becomes holiday-cropped.mp4. If a site limits the file size, Compress Video is first in the row under “Download MP4”. It takes the square straight from this page.

The crop is drawn and applied locally

The clip is played and cropped on your device: every frame of the result is decoded there and written back into an MP4 by your browser's own encoder. No frame is uploaded, and there is no account or queue. To continue in another tool, PulsarKit may store a local copy of your input or result in this browser. It can remain after you close the tab or restart the browser. Clear PulsarKit’s site data to delete it.

Frequently asked questions

Does cropping change the length or the sound?

The length stays the same. The sound is kept but re-encoded along with the picture, so it is not a byte-for-byte copy. In our check on October 21, 2026, the length, the frame rate and the stereo sound came through.

How do I get rid of black bars?

Pick the shape of the picture inside the bars, 16:9 for a widescreen film in a 4:3 file for instance, and build the video. The centred box cuts off bars that sit evenly on both sides. The bars are real pixels in the file, so removing them makes it smaller as well as better looking.

Why can I not make the box any size I like?

Because the box is not drawn by hand on this page. It is the largest box of the shape you pick, taken from the middle of the frame, and both sides are rounded to even numbers, which H.264 requires.

What is the difference from the aspect ratio tool?

Cropping removes part of the picture. Changing the aspect ratio keeps all of it and fills the space around it, with blur, colour or a centre cut. Use crop when the edges are unwanted, aspect ratio when the shape is wrong.

Does the file get smaller?

Usually yes, because the bitrate is scaled with the area you kept. In our check on October 21, 2026, a 9:16 crop of a 46 MB 1920 × 1080 clip came out at 16 MB, about a third. A clip that already has the chosen shape, or one left on Free, is encoded again and can come out heavier.

Which browsers does this work in?

Chrome 94 and later, Safari 26 and later, and desktop Firefox 130 and later, which have the H.264 encoder this needs. On anything else the page says so before you start.