Cropping a video online usually means uploading it, but this cropper runs entirely in your browser. You pick a target shape such as a square or a vertical frame, choose which part of the picture to keep, and optionally set an output resolution. Nothing is uploaded and the result is a standard MP4.
The tool is built on FFmpeg compiled to WebAssembly, so the decode and encode happen on your own machine. It can reshape a clip to 1:1, 16:9, 9:16 or 4:5, move the crop to the center, top, bottom, left or right, and scale the result to 1080p, 720p, 480p or a custom size. Because cropping rewrites pixels, the export re-encodes the video, which takes time in proportion to the clip length. There is no account, no watermark and no daily limit, and the whole job is free.
Trimming and cropping are different jobs, and mixing them up is why clips end up with black bars or a chopped off subject. Trimming changes how long a video is. Cropping changes the shape of the frame by deciding which pixels survive. This guide covers cropping, and it explains the two settings that decide the result: the aspect ratio and the crop position.
Video Cropper
Crop a clip to a square, vertical or widescreen frame, choose which part to keep, and resize the output. Runs locally, so nothing is uploaded.
Why widescreen video loses its edges on vertical platforms
Most footage is shot in a wide 16:9 shape, because that is what phones, cameras and screens default to. Vertical apps then show that wide frame inside a tall 9:16 window, and they handle the mismatch in one of two ways. They can shrink the whole picture and leave black bars above and below, or they can fill the screen by cutting off the left and right sides. Neither is wrong, but both take the decision out of your hands.
Cropping on your own terms does the same fill the frame job, except you decide what survives. You choose the target shape and the part of the picture to keep, so the tool trims the sides deliberately instead of letting the app guess where the subject is. That is the difference between a clip that looks intentional and one where a head is sliced in half.
Exact numbers vary by app and change over time, so treat the shapes in the table below as the common ones rather than fixed rules.
Which ratio to pick for each platform
| Platform | Where it plays | Frame shape |
|---|---|---|
| TikTok, Reels and Shorts | Vertical feed | 9:16 |
| Instagram square post | Grid and feed | 1:1 |
| Instagram portrait post | Feed, taller than a square | 4:5 |
| YouTube and desktop players | Widescreen player | 16:9 |
When in doubt, keep a 16:9 master and crop a 9:16 copy from it for vertical feeds. Cropping never adds anything that was not in the source, so starting from the widest version leaves the most room to choose.
How to crop a video online
The whole job happens in your browser and takes five steps.
- Add your video. Drop an MP4, WebM, MKV, MOV or AVI file into the upload box. The clip is read from your device into the page, and the FFmpeg engine downloads on first use.
- Pick an aspect ratio. Choose Original, 1:1, 16:9, 9:16 or 4:5. The overlay on the preview changes shape to show what will be kept.
- Choose which part to keep. Set the crop position to Center, Top, Bottom, Left or Right so the subject stays inside the frame.
- Choose an output resolution. Keep Original, or set 1080p, 720p, 480p or a custom width and height. This step is optional.
- Export and download. Press Crop and export, wait for the local encode, then download the MP4.
What the aspect ratio and crop position options mean
The aspect ratio chips decide the shape of the output frame. Original is the default, and it means no crop, so the frame keeps the shape it already has. The other four cover the shapes that social platforms care about.
1:1 keeps the largest square that fits, which is the shape of a grid post. 16:9 is the classic widescreen shape and matches most players. 9:16 turns a wide clip into a tall strip for vertical feeds. 4:5 is a portrait shape that is taller than a square but not as tall as a story.
Crop position decides which slice of the source survives. Center is the default and keeps the middle. Top and bottom move the crop vertically while the other axis stays centered, and left and right do the same horizontally. Position only matters when you pick a ratio, so it is ignored while the ratio is set to Original.
The tool always keeps the largest frame of the chosen ratio that fits inside the source and discards the rest, and it rounds both sides to even numbers so the encoder stays happy. For a wide 1920x1080 clip, a square crop keeps 1080x1080 and a 9:16 crop keeps a 608x1080 strip.
Cropping versus resizing
Cropping changes the shape of the frame by removing pixels from the edges. Resizing keeps the whole frame and changes how many pixels it is made of. A 1920x1080 clip cropped to a square becomes 1080x1080 with the sides gone, while the same clip resized to 720p stays 16:9 and is simply scaled to 1280x720.
This tool can do either one alone, or both in a single export, and it always crops first and scales second. The order matters, because the resolution you choose applies to the frame that is left after the crop.
The resolution menu lists Original, 1080p (1920x1080), 720p (1280x720) and 480p (854x480). Custom size lets you type an exact width and height between 16 and 7680; leave one side empty and it is worked out from the aspect ratio, and leave both empty to keep the current size. Scaling up does not add detail that was never in the source, it only makes the existing pixels larger.
Why crop locally instead of uploading
An upload based cropper is a reasonable pick for a clip you do not mind handing over, and it can be faster on a weak device because the encoding happens on someone else's hardware. It is a poor fit for the footage people actually crop, which is often an internal screen share, a product demo before launch or a private recording.
| Aihangsoft | Upload based cropper | |
|---|---|---|
| Where the video goes | Stays in the browser tab | Sent to their servers |
| Account | Not needed | Sometimes required |
| Limits | None beyond your own memory | Often a size or daily cap |
| Watermark | Never added | Sometimes added on free tiers |
| Works offline | Yes, after the first load | No |
The trade is raw speed and very large files. A server with real hardware encodes faster than a laptop, and browser memory sets a practical ceiling on how long a clip you can process. For the short clips a cropper is normally used for, keeping the file on your device usually costs nothing you would notice.
What this video cropper cannot do
These are the edges of the tool, and they matter more than the feature list when you are deciding whether it fits your job.
- It crops by preset only. You pick a ratio from 1:1, 16:9, 9:16 or 4:5 and a position from Center, Top, Bottom, Left or Right. There is no free drag box for an arbitrary rectangle, so a crop that is not one of those moves is not possible.
- The preview is a guide, not the final frame. The overlay is drawn over the player, while the export follows the real pixel dimensions, so trust the downloaded file over the preview box.
- Cropping always re-encodes. Because the pixels change, the video is written again as H.264 at CRF 20 with AAC audio, which takes time in proportion to the clip length.
- Long clips are limited by browser memory. The upload box suggests files under 500 MB and a few minutes long, and a very large clip may need to be handled in parts.
- The output is always MP4. Every export is an H.264 MP4 with a fast start index, whatever the input format was.
- There is no undo for the export. The pixels outside the crop are discarded, so keep the original until you have checked the result.
- The first run downloads about 30 MB. That is the FFmpeg engine, cached afterwards, and it is the price of encoding on your own machine.