MP4 to WebM Converter

Turn an MP4 into a WebM for websites, landing pages, and web apps that serve open video formats.

100% free
No signup needed
Browser-based

Why use Jupitrr's MP4 to WebM converter?

Made for the web

The video is re-encoded to VP9 or VP8 with Opus audio, the formats WebM was designed around.

Never uploaded

Your MP4 file is converted inside your browser and never leaves your device.

Free, no watermark

No signup, no install, and nothing added to your file.

How it works

Choose a MP4 file

Drop a MP4 video up to 1 GB onto the converter, or pick it from your device.

Keep WebM selected

WebM is already selected. You can switch to another output format if you need one.

Convert and download

The video is converted in your browser. Preview the WebM file, then download it.

What is a MP4 to WebM converter?

An open format for video on web pages.

WebM is an open, royalty-free video format designed for the web. It holds VP8, VP9, or AV1 video with Opus or Vorbis audio, and VP9 often gives a smaller file than H.264 at similar quality, which helps page speed.

Converting MP4 to WebM re-encodes the video, so it takes longer than a repackage. Modern Safari plays WebM too, but older Apple devices may not, so many sites offer WebM with an MP4 fallback.

When to reach for it

Website hero videos

Serve a lighter background or hero video on landing pages.

Web apps and games

Ship video assets in an open, royalty-free format.

Transparent-ready pipelines

Prepare clips for web stacks that standardize on WebM.

Documentation and demos

Embed product demos with the HTML video element.

Frequently asked questions

Why is WebM unavailable in my browser?

The converter only enables formats your browser can encode. Chrome, Edge, and Firefox can create WebM. If WebM is greyed out, try one of those browsers.

Is WebM smaller than MP4?

Often, when the WebM uses VP9, at similar visual quality. Results vary with the content, and a source MP4 that is already heavily compressed may not shrink further.

Should I use WebM or MP4 on my website?

Many sites serve WebM first with an MP4 fallback using two source elements in the HTML video tag. That gives modern browsers the smaller file while keeping older devices covered.

Is my MP4 file uploaded to a server?

No. The MP4 file is read and converted by your browser on your device. It is never sent to Jupitrr, and closing or refreshing the tab clears the working files.

Is there a file size limit?

Files up to 1 GB can be converted. Larger files can run out of browser memory, so trim or compress very long recordings first.

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