Crop Video Online
Reframe your video by dragging a crop box or picking a social aspect ratio. Everything runs in your browser - no upload, no watermark.
Cropping is useful when your video has the right moment but the wrong frame. You can cut away empty borders, remove a messy edge, center a face, or turn a horizontal recording into a vertical clip for Shorts, Reels or TikTok.
GrepCut runs the crop in your browser. That means your file stays on your device, which is especially helpful when you are working with personal recordings, client footage, school clips or internal screen recordings.
A 9:16 video is basically 16:9 turned upright. That sounds simple, but it changes the whole composition: your subject needs to live in the center column, not across the full width like in a landscape shot.
The 4:5 crop is a quiet feed trick. It takes up more vertical space than 1:1 without becoming a full-screen Story, Reel or Short, so it can make your video feel larger in mobile feeds while still looking natural.
Pinterest is the odd one out. A crop that feels perfect for Reels or TikTok can be too tall for a standard Pin, where 2:3 is often the safer visual shape.
Cropping does not just change the shape. If you crop a 1920 x 1080 landscape video into 9:16, the usable source area is roughly 607 x 1080 before scaling. If you start with 4K, you have much more room to reframe without the export looking soft.
Cropping changes the visible frame. It does not magically create extra detail outside the crop, so a tight 9:16 cut from a 1080p horizontal video will use fewer source pixels than the full original frame.
If your source is 4K, you usually have more room to reframe before the result looks soft on a phone screen. If your source is already small or heavily compressed, use the largest crop that still removes the unwanted area.
Changing aspect ratio can mean three different things: crop the sides, add padding, or stretch the image. GrepCut's crop tool is for real reframing, so your subject keeps its natural shape instead of being squeezed.
GrepCut uses browser media APIs to decode, crop and encode the video locally. The app can use WebCodecs where your browser supports it, with WebAssembly support for the processing pipeline.
Because there is no server upload step, you avoid the slowest part of many online video tools: sending a large file away and waiting for it to come back. Your browser reads the file, applies the crop coordinates, and exports an MP4.
Cropping video usually requires a new video encode because the visible frame has changed. GrepCut keeps the workflow simple and aims for a crisp export while preserving audio without re-encoding where the source allows it.
What crop ratio should you use for TikTok?
Use 9:16, ideally 1080 x 1920. Keep your subject, captions and important text near the center because platform controls can cover the edges and lower part of the frame.
What crop ratio should you use for Instagram Reels?
Use 9:16 for Reels and Stories. If you are posting to the main feed instead, 4:5 is often a better crop because it uses more vertical space than square while still fitting feed layouts.
What crop ratio should you use for YouTube Shorts?
Use 9:16 for a full-screen vertical Short. YouTube can also treat square videos as Shorts when they meet Shorts upload rules, but vertical is still the clearest crop when you want a phone-first result.
What crop ratio should you use for Pinterest?
Use 2:3 for standard Pins and 9:16 for full-bleed video Pins. If your video is mainly for Pinterest, test the 2:3 crop before assuming that a TikTok-style 9:16 version is the best fit.
Can you crop one video for every platform?
You can, but one crop is rarely perfect everywhere. If you want the safest set, export 9:16 for short-form vertical platforms, 4:5 for mobile feeds, 1:1 for carousel-style posts and 16:9 for YouTube or websites.
Can you crop a 16:9 video to 9:16?
Yes. Choose the 9:16 preset, then move the crop box over the part of the frame you want to keep. This is the usual choice when you want a vertical version of a horizontal clip.
Will cropping reduce video quality?
Cropping removes pixels outside the selected frame, so the export contains less of the original image. The result can still look sharp when the source has enough resolution, but a very tight crop from a small video can look softer.
Can you change aspect ratio without cropping?
Not with a crop alone. To fit a wide video into a vertical frame without cutting anything, you need padding, a blurred background or a design layout. Cropping keeps the frame filled by removing the outside area.
Does cropping remove the audio?
No. Cropping changes the video frame, not the audio track. GrepCut keeps the audio in sync and preserves it without re-encoding where possible.