MP4 – MPEG-4 Part 14
MP4 is the most widely supported video container. It usually holds H.264 or H.265 video with AAC audio and plays on nearly every phone, computer, TV and browser.
More MP4 conversionsDrop your MP4 files here
or click to choose MP4 files · up to 95MB each
How to convert MP4 to WEBM
- Choose your files. Click Select File or drag your MP4 files into the upload box. You can add many at once.
- Pick the settings. WEBM is already selected as the output format. The conversion starts as soon as a file is added.
- Download. Each file appears in the list when it is ready. Download them one by one, or all together with Download all.
Why convert MP4 to WEBM?
WebM is an open video format made for the web. With VP9 video it often makes smaller files than MP4 at similar quality, which is useful for background videos and clips on websites.
When to keep the MP4
Keep the MP4 for phones, TVs, editing software and social media, which all prefer MP4.
Tips for the best result
- The video is encoded with VP9 and the sound with Opus.
- WebM encoding is slower than MP4, so long videos take a while.
- Every current browser plays WebM.
Common problems and fixes
- An iPhone or video editor will not play the WebM.
- Support for WebM outside browsers is limited. Use MP4 for those.
- Conversion takes a long time.
- VP9 encoding is demanding. Trim the video first, or keep it as MP4.
WEBM – WebM
WebM is an open video format for the web using VP8/VP9 or AV1 video with Vorbis or Opus audio. All major browsers play it.
More WEBM conversionsConverting MP4 to WebM
- Re-encoded with widely compatible codecs (H.264/AAC for MP4, MOV, MKV; VP9/Opus for WebM).
Frequently asked questions
Is WebM better than MP4?
For websites it can be smaller. For everything else MP4 works on more devices.
Does MP4 to WebM keep the sound?
Yes. The audio is converted to Opus.
How do I convert MP4 to WEBM?
Click Select File or drop your MP4 file onto the upload box. The converted WebM appears in the list below with a download button. You can add many files at once and download them together as a ZIP.
Is it really free?
Yes. There is no sign-up and no watermark. To keep the service available for everyone there is a 95MB limit per file and a cap on how many files one connection can process in a short period.
Are my files stored?
Your upload is used only to make the converted file. Images are processed in memory; other files are written to a private temporary folder that is deleted as soon as the conversion finishes. Nothing is kept after the result has been sent back.
Will quality drop?
For images, a little, by design: the image is re-encoded at the Quality you choose (default 75%). Audio and video are re-encoded with high-quality settings; documents keep their text and layout as far as the target format allows. Converting never restores detail that is already missing from the original.
How this works: your file is uploaded over HTTPS and converted on this server with open-source engines (libvips for images, FFmpeg for audio and video, LibreOffice and Pandoc for documents, Calibre for ebooks, Ghostscript and Inkscape for PDF and vector files). Images are processed in memory; other files use a private temporary folder that is deleted as soon as the conversion finishes.