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Convert MP4 to WebM

Free MP4 to WebM converter that runs in your browser. No upload, no signup, no watermark. Files never leave your device.

Conversion Successful
100% local. Your file is processed in this tab and never uploaded.

How to Convert MP4 to WEBM

  1. 1

    Drop your MP4 file

    Drag it into the converter above, or click to browse. Nothing is uploaded.

  2. 2

    Adjust settings (optional)

    Trim, crop, resize, mute, or set quality from the sliders icon.

  3. 3

    Convert and download

    WEBM is preselected. The file converts in this tab and downloads when done.

Why Convert MP4 to WEBM?

WebM is royalty-free and built for the open web, which is why it embeds in an HTML5 video tag with no licensing questions hanging over it. At the same visual quality VP9 usually lands smaller than H.264, so pages carrying it load faster.

This conversion runs in your browser tab with WebCodecs, and the file never leaves your device.

MP4
WEBM
Container
MP4 (ISOBMFF)
Container
WebM
Typical codec
H.264 / H.265
Typical codec
VP8 / VP9 / AV1
Audio codec
AAC
Audio codec
Opus / Vorbis
Streaming friendly
Yes
Streaming friendly
Yes
Device support
Universal
Device support
Browsers, limited elsewhere
Typical use
Web, mobile, TV
Typical use
Web video

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Frequently Asked Questions

What codecs does the WebM output use?
VP9 for video and Opus for audio. Both are open and royalty-free, which is the whole reason WebM exists for web embedding.
Is WebM actually smaller than MP4?
Usually, at matched quality. VP9 compresses more efficiently than H.264, though the exact saving depends on the footage; high-motion clips benefit more than static ones.
Where does WebM play?
Chrome, Firefox, Edge, and Android play it natively, and recent Safari does too. For older devices or hardware players, keep an MP4 around; WebM is a web format first.
Is there a file size limit in the browser?
The browser converter handles MP4 files up to 500 MB. Larger files convert in TeraConvert Desktop, which has no size cap.
Is this conversion free, and is my file private?
Yes. The conversion runs in your browser tab, nothing is uploaded, and no account is needed. Files up to 500 MB convert here, limited to 3 conversions per day on this path; the desktop app has neither cap.

Converting a batch of clips to WebM?

TeraConvert Desktop converts a whole batch of MP4 files to WebM through native FFmpeg with no 500 MB cap.

Get TeraConvert for MacFree to download. This format unlocks with Pro.