Crop Video Online — Reframe MP4 for 9:16, 1:1, 4:5 or 16:9

Cut a video down to a framed region by dragging a crop box, with optional aspect-ratio locking for social formats.

Reframing footage means throwing away the parts of the picture you do not want and keeping the rectangle you do. Drag a box over the first frame, optionally lock it to a social aspect ratio, and every frame in the clip is recomposed to that same region and written back out as a fresh H.264 file with its audio intact.

How to crop a video

  1. Drop an MP4, MOV or M4V video onto the upload area, or click it to choose a file.
  2. Under Lock to aspect ratio, pick 9:16, 1:1, 4:5 or 16:9, or leave it on Free for any shape.
  3. Drag the box over the preview, or type Left, Top, Width and Height in pixels for an exact region.
  4. Read the output size in the note under the controls, which already accounts for rounding to even pixels.
  5. Click Export MP4 and save the cropped H.264 file with the download button.

Framing happens in source pixels, not screen pixels

The selection box you drag sits over a scaled-down preview, but the rectangle it reports is always expressed in the coordinates of the decoded frame. That distinction matters the moment your browser window is narrower than the footage: a box drawn over a half-size preview still maps onto exactly the pixels you framed, and the numeric Left, Top, Width and Height fields underneath show those true values so you can nudge them by hand.

Typing into those fields moves the box, and moving the box updates the fields. Neither is the source of truth over the other, which means you can rough in a region by eye and then round the numbers off to something tidy.

Aspect locks for the formats people actually publish to

The ratio selector offers Free, 1:1, 4:5, 16:9 and 9:16. When a ratio is active, dragging constrains the box to it, and pushing the box past an edge shrinks it rather than sliding it — that keeps the ratio mathematically exact instead of almost right, which is what matters when a platform rejects anything off by a pixel.

Choosing 9:16 on landscape footage is the common case: you are pulling a vertical slice out of a wide recording, and the box will naturally be tall and narrow. Position it over whatever the shot is actually about before exporting.

Crop ratios for TikTok, Reels, Instagram and YouTube

What the export actually produces

Because the picture geometry changes, there is no way to avoid re-encoding: every frame is decoded, redrawn into the new dimensions and compressed again as H.264. The audio track is decoded and re-encoded alongside it so the result is a complete, playable file rather than a silent one.

H.264 refuses odd frame dimensions, so a region that comes out to an odd number of pixels on either side is reduced by one. The notice above the export button always shows the exact output size before you commit to it.

Video cropper formats, output size and free limits

Your footage is cropped inside the browser tab

There is no upload step and no processing queue. The file is read from your disk, each frame is decoded, cut down to your rectangle and compressed again right in the page, and the finished MP4 appears as a download link. No server ever holds a copy of the original or the cropped result.

Questions people ask about Video Cropper

Does cropping reduce the file size?
Usually yes, because there are fewer pixels per frame to encode, but the amount varies with how much motion and detail remain inside the region you kept. A tightly cropped static shot compresses far better than a small window onto fast action.
Can I get the discarded picture back later?
Not from the exported file — the surrounding image is genuinely gone once it is written out. Keep your original recording if there is any chance the framing needs to change, and treat each export as a derived copy rather than a replacement.
Why does the box snap to a slightly different size when I lock a ratio?
A locked ratio is enforced exactly, so the box is resized to the nearest shape that satisfies it and still fits inside the frame. Shrinking to fit preserves the region you framed, whereas sliding the box would silently move it somewhere you did not choose.
Is there a length limit?
The free tier covers exports up to fifteen minutes of source material at full resolution with no watermark of any kind. Longer clips need Pro, and the counter shown above the controls tells you where the current file sits before you start.
What video formats can I crop?
MP4, MOV and M4V files, which are read as MP4-family containers. The page also needs to decode the picture, so H.264 video is the safest input; if the browser cannot read a file it shows an error and suggests an H.264 MP4 instead. The export is always an MP4.
Will cropping reduce video quality?
The pixels you keep are not scaled, but every frame is compressed again as H.264 with a 6 Mbps target, so there is one extra generation of lossy compression. For most phone and 1080p footage that is hard to see; large 4K crops can lose fine detail. Keep the original if quality matters.
How big a video file can I crop?
There is no fixed file-size cap. The limit is your browser tab's memory, which browsers typically cap near 2GB: the page reads the whole file into memory and keeps a second copy for decoding the audio, so files of several hundred megabytes can fail on devices with little RAM.
How do I crop a video for TikTok or Instagram Reels?
Choose 9:16 under Lock to aspect ratio, then drag the tall box over the part of the shot that matters, usually the speaker or subject. Export the MP4 and upload it to the app. For an Instagram feed post rather than Reels, 4:5 or 1:1 usually fits better.
What is the difference between cropping and resizing a video?
Cropping cuts away the edges and keeps a smaller region at its original pixel size, which can change the shape of the frame. Resizing scales the entire picture up or down without removing anything, so the shape stays the same. This page crops; scaling is a job for a video resizer.
Can I crop a video on my phone?
Only in a mobile browser that supports WebCodecs video encoding, because every cropped frame has to be re-encoded on the device. The page checks for the encoder when it loads and shows a notice instead of a working export when it is missing. Support differs between browsers and versions.

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Content reviewed 2026-09-27.