Convert video to WebM

Free, no login, and your file never leaves your device.

Open the Convert Video tool

video to WebM, converted on your own machine

Converting video to WebM normally means handing your file to a website that uploads it, processes it on a machine you cannot inspect, and asks you to trust a retention paragraph. FileForge removes that step: the Convert Video tool runs inside this browser tab, so a video file becomes WebM without ever crossing the network.

Transcode video between MP4, WebM, MKV, and AVI using a real FFmpeg build running as WebAssembly in your tab. Pick a quality preset and watch the live encoder log. Everything happens locally in your browser: nothing is uploaded, stored, or logged.

Because the conversion happens on your hardware, throughput depends on your CPU rather than a shared free tier — there are no file-size caps, no watermarks, no daily quotas, and no paid tier that unlocks the real feature set. It also means the page keeps working offline in the browser once loaded, which is handy for confidential material on a locked-down laptop or a phone in aeroplane mode. One honest caveat: the FFmpeg engine is roughly 30 MB and downloads once per session. Large or long files are limited by your device's memory.

Read how the in-browser processing works.

How to convert video to WebM

  1. 1

    Open Convert Video

    Open the Convert Video page on FileForge. No sign-up, install, or extension is needed — the tool loads as a normal web page.

  2. 2

    Add your file

    Drop your file into the panel, or click to browse. The file is read locally in your browser and is never uploaded.

  3. 3

    Choose your settings

    Adjust the options in the settings panel — mp4 · webm · mkv · avi, via ffmpeg wasm — until the result matches what you need.

  4. 4

    Run and download

    Press the action button, wait for processing to finish on your own CPU, then download the result straight from the page.

video to WebM — frequently asked questions

Do I need to create an account to use Convert Video?
No. FileForge requires no sign-up or login — just open the tool and use it.
Is Convert Video really free?
Yes, completely free with no hidden limits or premium paywall.
Does Convert Video upload my file to a server?
No. Everything runs locally in your browser. Your file is never uploaded, stored, or transmitted anywhere.
Is there a file size limit?
There is no artificial limit. The practical ceiling is your device's available memory, so very large files work best on a desktop browser with plenty of free RAM.
Does Convert Video work offline in the browser?
Once the page (and, for audio and video, the FFmpeg engine) has loaded, the tool keeps working without a network connection because all of the processing code already lives in your browser.
Is Convert Video private enough for confidential documents?
Yes. Because the file is processed on your own CPU, contracts, medical scans, ID photos and payroll data never travel over the network — you can verify that with your browser's network tab open.
Which browsers are supported?
Any modern browser with WebAssembly support — Chrome, Edge, Firefox, Safari, and their mobile versions. No plugins or extensions are required.
What are the limitations of Convert Video?
The FFmpeg engine is roughly 30 MB and downloads once per session. Large or long files are limited by your device's memory.

Related conversions

Convert video to MP4