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MP4 to WebM

Convert an MP4 to a smaller VP9 WebM for the web — in your browser.

Select a video file

MP4, MOV — converted to VP9 / Opus WebM in your browser

Click to choose, or drop a file here

How to MP4 to WebM

  1. 1

    Add your MP4

    Drop in the .mp4 or .mov file — it's read in your browser.

  2. 2

    Convert

    Click Convert to WebM; the video is re-encoded as VP9/Opus with the WebCodecs API.

  3. 3

    Download

    Save the WebM — smaller than the MP4 and ideal for websites.

Related PDF tools

Compress VideonewShrink an MP4, MOV or WebM by re-encoding it at a lower bitrate — in your browser, nothing uploaded.WebM to MP4newConvert a WebM video to an H.264 MP4 that plays everywhere — in your browser.Video to GIFnewTurn a short video clip (MP4, MOV, WebM) into an animated GIF — in your browser.Trim VideonewCut a video down to just the part you want, in your browser.

MP4 to WebM — frequently asked questions

Is my file uploaded?+

No. The MP4 is decoded and re-encoded to WebM entirely in your browser with the WebCodecs API.

Why convert MP4 to WebM?+

VP9 WebM is typically 20–40% smaller than H.264 at the same quality and is well suited to websites and open-source workflows.

Does WebM play everywhere?+

It plays in every modern desktop and Android browser, but not natively on iOS Safari or in many video editors — keep an MP4 too if you need those.

Which browsers work?+

Chrome, Edge and Safari 17+ can decode the MP4 and encode VP9.

Do you upload my files to a server?+

No — every tool here processes your files entirely on your device, and nothing is uploaded to a server. The only exception is the AI tools, which send the extracted text (not the file) to Claude to do their work.

Is there a file size limit?+

There's no artificial limit we impose, but since processing happens in your browser, very large files (500+ MB or 1,000+ pages) are limited by your device's memory rather than by us.