How to use the Crop Video tool
- Select your fileClick “Choose File” or drop it into the box above. Nothing is uploaded — the file is opened locally by your browser.
- Adjust visuallyDrag the frame or its corners to select the area to keep, or pick a preset aspect ratio.
- Click “Crop video”Processing takes a few seconds. When it is done, download your file — or all results as a single ZIP.
Why use ConvertMathly?
Files are processed on your device and never uploaded. Close the tab and they are gone.
No account, no daily cap, no queue and no watermark — convert as much as you want.
The same engine used by professional video tools, running in your browser via WebAssembly.
Windows, Mac, Linux, Chromebook, iPhone and Android — any modern browser, nothing to install.
Frequently asked questions
Is Crop Video free?
Yes. Crop Video is free to use as often as you like — no sign-up, no watermark and no file limits.
Are my files uploaded?
No. ConvertMathly processes files directly in your browser, so they never leave your device. This is safer than tools that upload documents to a server.
Why does the first run take longer?
A one-time download of the video engine (~30 MB) happens on first use and is cached afterwards.
Does it work on mobile?
Yes — on iPhone, iPad, Android, Windows, Mac, Linux and Chromebook, in any modern browser.