What is WebM?
WebM (VP8/VP9)
WebM is a royalty-free, open video format developed by Google specifically for the web. It uses VP8 or VP9 codecs to deliver high-quality video at small file sizes, making it ideal for HTML5 video playback.
History of WebM
WebM was launched by Google in 2010 specifically for HTML5 video on the open web. It uses royalty-free codecs (VP8/VP9 for video, Vorbis/Opus for audio) — meaning anyone can implement or use it without paying licensing fees. Designed to be the modern, open answer to MP4 for streaming and web playback.
Technical specs
- Format name
- WebM (VP8/VP9)
- File extension
- .webm
- MIME type
- video/webm
- Category
- Video
- Compression
- Lossy compression
When to use WebM
Reach for WebM when you need html5 web video embedding, modern browser-based streaming, open-source video projects. It excels at these scenarios because open source and royalty-free and excellent web compression.
Pros
- +Open source and royalty-free
- +Excellent web compression
- +Native support in Chrome, Firefox, Edge
When to avoid WebM
Avoid WebM when limited support on ios and safari, and slower encoding than h.264. In those cases, look at the alternatives below.
Cons
- −Limited support on iOS and Safari
- −Slower encoding than H.264
- −Less editing software support
Common uses for WebM
- HTML5 web video embedding
- Modern browser-based streaming
- Open-source video projects
Alternatives to WebM
For broader hardware compatibility, MP4 (H.264) is more universal. For movie archival with multiple subtitles, MKV.
Convert WebM to…
Convert to WebM from…
WebM — Frequently Asked Questions
Is WebM still used in 2026?
Is WebM still used in 2026?
Yes, WebM is actively used. HTML5 web video embedding keeps it relevant.
Can I open a WebM file on my phone?
Can I open a WebM file on my phone?
Android (Chrome) handles WebM. iPhone Safari has limited support — converting to MP4 ensures it plays everywhere on iOS.
Why is my WebM file so different in size from other files?
Why is my WebM file so different in size from other files?
WebM file sizes depend on encoder settings (bitrate, resolution, quality). For smaller files, re-encode at a lower bitrate or convert to a more compressed format.
Can I convert WebM to another format for free?
Can I convert WebM to another format for free?
Yes — Zen Convert converts WebM files to every other video format we support, for free, in your browser. No signup, no watermark.
Is WebM open-source?
Is WebM open-source?
Yes — WebM is fully open-source and royalty-free. You can implement, distribute, and use it without paying any licensing fees.