Updated June 2026 · runs 100% in your browser

Video Converter

Convert video between MP4, WebM, MOV and MKV on your device. No upload, no sign-up — and because encoding runs in your browser, it works best on shorter clips.

Drop a video here

or click to choose

🔒 Converted on your device · 0 bytes uploaded

Convert to

First file loads the converter engine (~25 MB). Video encodes on your device, so shorter clips finish fastest.

How it works

ConvertCabin loads a local copy of FFmpeg compiled to run inside this browser tab. Your video is decoded, re-encoded and saved entirely on your device — nothing is uploaded.

The first conversion downloads the engine (about 25 MB) and your browser caches it. Because encoding runs locally and single-threaded, it's slower than a server — so it works best on shorter clips, and stays completely private.

About converting video

This re-encodes your video with FFmpeg right on your device. MP4 (H.264) is the most widely compatible; WebM is ideal for the web. Browser-based encoding is slower than a server and uses memory, so short clips convert best — for long 4K footage a desktop app will be faster.

Frequently asked questions

How do I convert a video?

Drop a video, choose the output format, and download the result once it finishes — all in your browser.

Can it handle long or 4K videos?

It can, but encoding runs on your device and single-threaded, so long or high-resolution clips can be slow. Shorter clips are the sweet spot.

Is my video uploaded?

No. It is converted on your device by a local copy of FFmpeg and never sent to a server.