MP4 to WebM converter
Convert MP4 to WebM free online. Shrink videos with VP9 for faster HTML5 streaming. No signup, 500 MB limit, files auto-deleted in 1 hour.
Drop a file to convert here
or click to browse
About WebM Video Format
Common Use Cases
- Web video streaming with better compression
- Open-source video hosting
- Modern browser video playback
MP4 is the default container for most video you encounter, but when the video is headed for a website, WebM is usually the smarter choice. WebM was designed for the web from day one. It streams faster, compresses better at comparable quality, and plays natively in every modern browser without any plugin or proprietary codec.
WebM with VP9 or AV1 encoding typically delivers 25-50% smaller files than H.264 MP4 at visually equivalent quality, which directly translates into faster page loads and lower bandwidth bills.
Why Convert MP4 to WebM?
Smaller files, lower bandwidth costs
For a site serving video at scale, WebM can cut egress bandwidth roughly in half versus MP4 at the same perceptual quality. Over a month of traffic, the savings on CDN and hosting bills often more than pay for the conversion effort.
Faster initial playback on the web
Smaller files mean the browser can start playing sooner and buffer less mid-stream. Users on mobile and slower connections notice the difference immediately, which improves engagement and reduces abandonment.
Open, royalty-free codecs
WebM uses VP8, VP9, or AV1, which are all open standards with no licensing fees. H.264 inside MP4 is patent-encumbered and may require licensing for commercial use, while WebM is free to use and ship forever.
First-class HTML5 support
Every current browser (Chrome, Firefox, Edge, Safari on recent versions) plays WebM in the native <video> tag. No Flash, no plugin, no fallback player library required for the common case.
When to use each
Use MP4 when...
- Editing in Premiere, Final Cut, or Resolve
- Playing on smart TVs and older set-top boxes
- Uploading to platforms that require MP4
- Sharing via AirDrop or iMessage
- Archiving master footage
Use WebM when...
- Hosting video on a website or web app
- You want smaller files at equal quality
- Background videos, autoplay loops, hero reels
- Reducing CDN bandwidth costs at scale
- Serving video to mobile users on metered data
Common use cases
- Web video streaming with better compression
- Open-source video hosting
- Modern browser video playback
How to use
- Upload your MP4 file. Drag and drop your MP4 onto the upload area, or click to browse for a file. Uploads are limited to 500 MB per file, which handles most short web clips. For longer videos, trim or compress first before uploading.
- Start the conversion. Click Convert File and our servers re-encode the video with FFmpeg. The H.264 stream is transcoded into VP9, audio is converted to Opus, and everything is packed into a WebM container optimized for the web.
- Download your WebM file. A download link appears when processing finishes. Drop the WebM into your website, web app, or CDN and serve it directly from an HTML5 video tag. Uploaded and converted files are automatically deleted within 1 hour.
Frequently asked questions
- Will my WebM play on iPhone or iPad?
- No. Apple has never added native WebM support to iOS or Safari in a reliable way. That is why the standard pattern for web video is to ship both a WebM and an MP4 using two source tags inside a single video element, so modern browsers get the smaller WebM and Apple devices fall back to the MP4.
- How much smaller will my WebM be than the MP4?
- It depends on the source, but WebM with VP9 is often 25 to 50 percent smaller than H.264 MP4 at visually equivalent quality. AV1 can go even further for high-resolution content. The exact savings depend on how efficiently the original MP4 was encoded.
- Will conversion reduce quality?
- WebM uses VP9 or AV1, so the video has to be re-encoded from H.264. That means one additional pass of lossy compression on top of the MP4. In practice the quality loss is usually imperceptible at reasonable bitrates, especially when converting from a high-quality MP4 master.
- Is there a file size limit?
- Yes, 500 MB per file. For longer videos, consider trimming or pre-compressing the MP4 before uploading. Web-targeted clips are usually well under the limit anyway.
- Is MP4 to WebM conversion free?
- Yes. Anonymous visitors can convert for free with a daily limit, registered FileFactory users get a higher daily cap, and Premium or Lifetime members get unlimited conversions with priority processing.
- How long are my files stored?
- Uploaded MP4 files and the converted WebM output are automatically deleted from our servers within 1 hour. Transfers are encrypted and your files are never shared with third parties.
- VP9 or AV1, which one does this converter use?
- The converter produces VP9 WebM by default, because VP9 has the broadest browser support while still delivering excellent compression. AV1 offers even better efficiency but takes much longer to encode and has narrower playback support in older browsers, so VP9 is the practical choice for most web deployments today.