Convert video

Convert video between MP4, WEBM and MKV in the browser, with sensible H.264 and AAC settings already chosen.

Runs in your browser only. Your files are never sent to a Kit server.

How it works

Uses single-thread FFmpeg WASM. Large files can be slow; codec support is limited.

Format

Drop files here

or browse from your device

You can also paste from the clipboard

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Common questions

Where do my files actually go?: Nowhere. They are read and processed inside this tab and written back to your disk when you save. The network log on this page shows exactly what crossed the wire.
If tools run in a browser, isn’t my file uploaded somewhere?: No. Opening a tool downloads the tool’s code to your device, once, the way installing an app does. From then on the tool runs on your device and reads your file from your disk — nothing about the file is sent anywhere. The network log on this page shows it: the requests you see are Kit fetching its own code and, once, currency rates.
Does Kit work offline?: Yes. Once a tool page has loaded — or once Kit is installed — the tools keep working with no connection. Offline access in Settings downloads the languages and tools you pick in advance. The currency converter is the only exception, and only for fresh rates.