UtilityKit

500+ fast, free tools. Most run in your browser only; Image & PDF tools upload files to the backend when you run them.

Video Cropper

Crop a rectangular region out of any MP4, WebM or MOV using a draggable selection rectangle.

About Video Cropper

Video Cropper lets you cut a rectangular region out of any MP4, WebM or MOV video, all inside your browser. After uploading a clip, you draw a selection rectangle directly on the inline preview — drag from corner to corner — or type pixel-exact X, Y, width, and height values. The tool then re-encodes only that region using ffmpeg.wasm's crop filter and returns a new MP4. This is useful for changing aspect ratio (16:9 → 9:16 for vertical video, square for Instagram), removing letterboxing or watermarks at fixed corners, or zooming into a specific area of a screen recording. Nothing uploads — everything happens on your device.

Why use Video Cropper

  • 100% private — your video never leaves your device
  • Pixel-accurate cropping — type exact coordinates or drag visually
  • Live preview rectangle so you can see the crop region before encoding
  • No file size limits imposed by server quotas
  • No watermarks, no signup, completely free
  • Works offline after the first ffmpeg.wasm cache

How to use Video Cropper

  1. Click or drag your MP4, WebM or MOV onto the upload area.
  2. The video appears in an inline preview with a draggable crop overlay.
  3. Drag from one corner to the opposite corner on the preview to draw a crop rectangle.
  4. Or type pixel-exact X, Y, Width, Height values into the number inputs below.
  5. Use the live preview rectangle to fine-tune the region.
  6. Click 'Crop Video' and wait for ffmpeg.wasm to re-encode the region.
  7. Preview and download the cropped result as MP4.

When to use Video Cropper

  • Converting horizontal 16:9 footage to vertical 9:16 for TikTok / Reels / Shorts
  • Cropping to a square aspect ratio for Instagram feed videos
  • Removing letterboxing or pillarboxing from old or transferred footage
  • Cropping out a watermark or burned-in timecode at a fixed corner
  • Zooming into a specific app window in a full-desktop screen recording
  • Trimming dashcam side mirrors or steering wheel from the frame

Examples

Convert 16:9 to vertical 9:16

Input: 1920×1080 MP4, crop to 608×1080 from x=656,y=0

Output: 608×1080 vertical MP4 ready for Reels / TikTok / Shorts

Square crop for Instagram

Input: 1920×1080 MP4, crop to 1080×1080 from x=420,y=0

Output: 1080×1080 square MP4 ready for IG feed

Remove watermark from corner

Input: 1080p MP4, crop to 1820×1020 from x=20,y=20

Output: Slightly cropped 1820×1020 MP4 with corner watermark removed

Tips

  • For TikTok / Reels (9:16), crop to 1080×1920 from the centre of a 1920×1080 source — drag from x=420,y=0 to x=1500,y=1080.
  • For Instagram square (1:1), use the smaller of source width/height and centre the crop.
  • Type exact pixel values rather than drawing if you need a specific aspect ratio.
  • Use the Video Resize & Converter tool first if you need to upscale before cropping.
  • Cropping works on the source resolution — even if the preview is shrunk to fit, your pixel inputs map to the original size.
  • After the first run ffmpeg.wasm is cached so subsequent crops start instantly even offline.

Frequently Asked Questions

Does my video leave my device?▾
No. Cropping runs 100% locally in your browser using ffmpeg.wasm — your file is never uploaded to any server.
Why does it require Chrome / Edge?▾
ffmpeg.wasm needs SharedArrayBuffer for multi-threaded WebAssembly. SharedArrayBuffer requires COOP/COEP headers, which Chrome, Edge, Brave and Arc all support.
What is the file size limit?▾
No server limit. Your browser tab caps out around 2 GB; practically, files up to ~500 MB process reliably.
Does cropping reduce quality?▾
Cropping requires re-encoding the video stream, so technically yes. The default CRF 23 is visually transparent for most content. Audio is stream-copied untouched.
Why does my crop have to be even pixels?▾
H.264 and most video codecs require even-numbered widths and heights for chroma subsampling. The tool snaps to even values automatically.
Can I crop without re-encoding?▾
No. Stream-copy preserves frame data exactly, so cropping mathematically requires decoding and re-encoding pixels.
How do I crop to a specific aspect ratio like 9:16?▾
Set width to your target (e.g. 1080), then height = width × 16/9 (e.g. 1920). Use the number inputs for exact values.
Why does the first run take longer?▾
ffmpeg.wasm (~30 MB) downloads on first use and is then cached by the browser for instant subsequent runs, even offline.

Explore the category

Video Trimmer Cut and trim MP4, WebM, MOV videos to exact start and end times, right in your browser. Video Compressor Reduce MP4, WebM and MOV file size with adjustable H.264 CRF compression — runs entirely in your browser. Video Merger Concatenate multiple MP4, WebM or MOV clips into one continuous video file — no upload required. Video Rotator Rotate MP4, WebM and MOV videos 90, 180 or 270 degrees, or flip horizontally / vertically. Video Mute / Audio Remover Strip the audio track from any MP4, WebM or MOV video, lossless and instant. Video Looper Loop an MP4, WebM or MOV clip a chosen number of times into one continuous output file.
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Glossary

Crop filter
FFmpeg video filter (crop=W:H:X:Y) that extracts a rectangular region from each frame.
Aspect ratio
Ratio of width to height. 16:9 (landscape), 9:16 (vertical), 1:1 (square), 4:3 (classic TV).
Chroma subsampling
Compression technique that encodes color at lower resolution than luminance — requires even pixel dimensions.
Letterboxing
Black bars at top and bottom when widescreen content is shown in a 4:3 frame — cropping removes them.
ffmpeg.wasm
WebAssembly port of FFmpeg that runs locally in your browser tab.
SharedArrayBuffer
JS memory primitive needed for multi-threaded WebAssembly; gated by COOP/COEP cross-origin isolation.