Video Resizer/Cropper
Resize a video to new dimensions or crop to a specific aspect ratio (1:1, 9:16, 16:9) for social platforms.
What is Resize & Crop?
A video resizer and cropper for reformatting landscape footage into vertical or square social formats — and back again.
How it works
An ffmpeg scale/pad/crop filter chain is built from your target box and fit mode, then the video is re-encoded at the quality you choose. Aspect-ratio and platform presets fill in the exact pixel sizes the platform expects.
- Load your file. Drag a file onto the drop zone or pick one from your device. It is read locally by the browser and never uploaded.
- Set the options. Adjust the handles, format, quality or threshold controls — the preview updates as you change them.
- Process and download. Run the tool, then download the result. Compare the reported before/after size for compressors and converters.
Examples
A 42 MB podcast episode → 9 MB MP3
Trim the intro, normalise to −16 LUFS, and export at 96 kbps mono — a typical interview lands around a fifth of the original size.
A phone video with the wrong orientation
Rotate 90° and the width/height swap in the output, so it plays upright in every player instead of relying on metadata flags.
Common mistakes
Expecting instant encoders
Video encoding runs in single-threaded WebAssembly, so a clip takes roughly its own length (or a little longer) to re-encode. Stream-copy operations are near-instant by comparison.
Re-encoding when a copy would do
Trimming, removing audio and joining same-codec clips can copy streams without re-encoding — pick the copy option when it is offered to avoid any quality loss.
Ignoring the first-load download
The media engine is about 31 MB and is fetched on first use, then cached. The first conversion on a connection is slower than every later one.
Frequently asked questions
Crop, pad or stretch?
Crop fills the frame edge to edge (best for social feeds), pad keeps the whole original frame with bars (best for preserving composition), and stretch forces the size (avoid unless the ratio is already close).
Why must the dimensions be even numbers?
H.264 and VP9 encode in 2×2 blocks. Odd dimensions either fail or get silently rounded, so the tool rounds to even values for you.
Can one video go to several sizes at once?
Not in one run — each size is its own export, which keeps the memory footprint low for large files.