Video Aspect Ratio
Crop videos to 9:16, 1:1, 16:9 or 4:5
Drop a video file (MP4, WebM, MOV, AVI, MKV)
🔒 Files never leave your device
⚡ Uses FFmpeg WebAssembly. First run downloads ~30 MB (cached after). Encoding takes roughly 1–5× the video's duration.
How it works
- 1Upload your video
Drop or select a video file.
- 2Configure options
Choose the settings that fit your use case.
- 3Download
Save the processed video to your device.
About Video Aspect Ratio
Video Aspect Ratio — free online tool that runs entirely in your browser via FFmpeg WebAssembly. Your video never leaves your device. Video Aspect Ratio on DashConvert runs entirely inside your browser using modern JavaScript APIs — no server ever sees your files. That means faster conversions, complete privacy, and no upload limits.
Whether you need to crop videos to 9:16, 1:1, 16:9 or 4:5 for work, study, or personal use, this tool is free to use as many times as you need. There are no watermarks, no sign-up, and no ads inside your documents.
Frequently asked questions
Are my videos uploaded?
Never. Processing runs entirely in your browser using FFmpeg WebAssembly.
Why is it slow?
Video encoding is CPU-heavy. Expect roughly 1–5× the video's duration for encoding. First-time load also downloads ~30 MB of FFmpeg (cached after).
What's the file size limit?
Depends on your device's memory. Files up to ~1 GB usually work; multi-GB files may crash the tab.