Video FFmpeg WASM

Convert WEBM to MP4

Free, browser-based WEBM to MP4 converter. Files are processed locally in your browser and not uploaded to any server.

.webm.mp4
Multiple files supported

Drop .WEBM files to convert

Drop multiple files at once - they'll be converted sequentially

Processed entirely in your browser - never uploaded

🔒No uploads
⚡WebAssembly
💻Runs locally

How it works

Three steps to convert WEBM to MP4

  1. 01

    Drop your .webm file

    Drag and drop onto the tool above, or click to open the file picker.

  2. 02

    Browser converts it

    The FFmpeg WebAssembly engine runs locally in your browser tab.

  3. 03

    Download .mp4

    Instantly grab your converted file. The original is never modified.

FAQ

Common questions

Is this WEBM to MP4 converter really free? +

Yes, completely free with no sign-up required. Run it as many times as you like.

Are my files safe? +

Your file is processed locally in your browser tab and is not uploaded to any server.

What is the maximum file size? +

There is no hard limit enforced by the tool - available RAM in your browser tab is the practical ceiling.

Does it work offline? +

Once the page and its conversion assets have loaded, conversions run locally in the current tab. Reloading the site still needs network access unless you cache it separately.