Crop Video Online

How to crop a video

1. Choose the video above. MP4, MOV, M4V, WebM and MKV open, as long as your browser can decode the picture. The file card shows the resolution, length and codecs.
2. Pick a shape in the Shape menu: 9:16 vertical, 1:1 square, 4:5 portrait, 16:9 wide, 4:3, 21:9, or Free for any rectangle.
3. Drag the box over the preview to the part of the picture you want to keep. With a fixed shape, the Size slider shrinks the box (down to 20%) without changing its shape. With Free, separate Width and Height sliders set each side.
4. Press "Crop video" and leave the tab open while the progress bar runs.
5. Download the MP4. The result card states the new frame size and how the video was encoded.

Crop, resize or trim?

Three edits get called "cropping" in everyday speech, and they do different things to a file:

Crop

removes the edges of the picture. The video keeps its full length; the frame becomes smaller.

Resize

scales the whole picture to new dimensions, and when the shape changes it adds bars, cuts edges or stretches.

Trim

removes time from the start or end. The frame is untouched.

If you want the whole picture to fit a new shape with bars around it, resize the video instead. If you want to cut seconds off the beginning or end, trim the video. If you want only the middle part of a wide frame, this is the right page.

Which shape to choose

• 9:16 vertical for TikTok, Reels, Shorts and Stories, where the video fills an upright phone screen.
• 1:1 square for posts that should look the same in a feed and in a grid of thumbnails.
• 4:5 portrait for feed posts that take up more of the screen than a square while still fitting a scrolling feed.
• 16:9 wide to turn a squarer or taller clip into standard widescreen, or to cut a 21:9 clip down for a TV or a slide deck.
• 4:3 to recover slides or older footage that was placed inside a 16:9 frame with bars at the sides.
• 21:9 for a cinematic strip cut from a 16:9 clip.
• Free when only one side needs trimming, such as a taskbar along the bottom of a screen recording.

What cropping does to the resolution

The crop keeps the pixels inside the box at their original size. It doesn't enlarge them, so the output is smaller than the source in at least one direction. From a 1920×1080 video:

9:16 at full size

about 608×1080: the full height and a narrow slice of the width

1:1 at full size

1080×1080

4:5 at full size

864×1080

16:9 with Size at 50%

960×540, which plays back as a 2× zoom

Dimensions are rounded to even numbers, because video encoders need them.

A 608×1080 vertical clip still fills a phone screen, but the player enlarges it, so it looks softer than a clip filmed upright at 1080×1920. Cropping can't add the missing detail. If an upload form insists on exact dimensions, crop first and then use the resize tool, or, for a 16:9 to 9:16 job, the horizontal to vertical converter, which has a "Scale to 1080×1920" option. Scaling up changes the pixel count, not the sharpness.

Re-encoding, sound and speed

Cropping changes every frame, so the video has to be decoded and encoded again; there is no copy-only shortcut as there is for a rotation flag. The tool uses the browser's WebCodecs encoder and writes an MP4, using H.264 when the browser offers it. It chooses a bitrate from the new frame size and the original file's bitrate, so the cropped picture stays close to the source rather than being squeezed. The sound is copied as it was when MP4 can hold it.

How long it takes depends on your computer and the length and resolution of the clip. A short phone clip finishes quickly; a long 4K recording is real work for a laptop. Large results are written to the browser's private storage where available instead of being held in memory, but the tab still has to stay open until the download appears.

Examples

Limits

• The box is fixed for the whole video. It doesn't follow a moving subject, detect faces or reframe automatically. If the subject moves across the frame, trim the video into parts and crop each part separately.
• One crop per file: there is no pan or zoom that changes over time.
• Zooming in shows any blur and noise that was in the original.
• The output is always MP4, even when the source is WebM or MKV.
• The browser has to decode the source. iPhone HEVC files open only where the device supports HEVC decoding; the HEVC compatibility guide explains where that is.
• Encoding needs WebCodecs video encoding: a current Chrome or Edge, Safari 16.4 or later, or Firefox 130 or later on a computer. If the browser can't encode, the tool says so instead of failing silently.
• To hide a logo or a face without cutting the frame, blur that part of the video instead; cropping always removes a whole strip.

After cropping

A cropped clip for social media usually needs captions next. Open the MP4 in the free subtitle editor, type or import subtitles, or create them from the speech with the AI subtitle generator at 1 credit (0.1¢) per minute, with a minimum of 5 credits per file. Turn on the safe-area guide for the new shape so the words stay clear of app buttons.