Convert MP4 to WebM
WebM is an open format made for the web. Convert MP4 clips for HTML5 video and web apps.
Going the other way? Convert WebM to MP4
- Formats
- MP4
- Max size
- 4 GB
- Price
- Free
Drop files here
or browse your device · paste with Ctrl/⌘ V
MP4 · up to 4.00 GB per file
Related tools
How to convert MP4 to WebM
- Add your MP4 videos — up to 10 at a time, up to 4 GB each.
- WebM is already selected; there's nothing else to set.
- Click Convert and download your WebM files.
What is MP4?
MP4 is the most compatible video format: it plays on phones, browsers, TVs and in every editor. Inside it usually holds H.264 (sometimes HEVC or AV1) video with AAC sound.
What is WebM?
WebM is an open web video format (VP8, VP9 or AV1 video with Opus or Vorbis sound), common for browser screen recordings and web clips. Many phone galleries, editors and messaging apps don't accept it.
What changes when you convert MP4 to WebM
When the video and sound inside can go into WebM as they are, they're copied without re-encoding — fast and with no quality loss. Otherwise they're re-encoded with your browser's encoder.
Does converting MP4 to WebM reduce quality?
Not when the streams can be copied as they are (common for MP4 to WebM). If they have to be re-encoded, the default quality keeps the difference hard to see.
Will the WebM be smaller than the MP4?
About the same in most cases — check the result screen, which shows both sizes.
Can I convert several MP4 files at once?
Yes — up to 10 files of 4 GB each in one go. Several results download together as a ZIP.
Is my video safe?
Yes. Your video is only used to create your result — it’s never shared and never used to train AI.
Which browsers work?
Recent Chrome, Edge and Safari 17+ work best. Firefox supports most tools; if a codec isn't available we'll tell you.