Compress WebM Online - Free
Shrink a WebM file without it falling apart. It comes back as a small MP4 that plays everywhere.
- Free to start
- In your browser
- Up to 1GB
Compress WebM in 3 steps
Upload your WebM
Drag and drop the WebM file, or click to browse. Anything under 1GB.
A balanced level is pre-set
Compression and resolution start at a level most people cannot tell from the original. Push either further in the panel if you need it smaller.
Compress and download
The smaller file downloads as MP4. Create a free account to download it, or keep editing in REQO.
Why WebM files are big, and what comes back
WebM is the open, royalty-free container built for the web. It is what most browser-based screen recorders produce, and VP9 packs the same picture into noticeably less data than H.264.
Most editing software, phones and TVs will not open a WebM file.
Social platforms and messaging apps frequently reject the extension outright.
The compressed file comes back as MP4 (H.264 video, AAC audio), not WebM. That is where most of the saving comes from: H.264 in MP4 is the most efficient format that every phone, browser and upload form accepts. If something downstream insists on WebM, convert the result back with the MP4 to WebM converter.
Container
Typical codecs
Plays on
File size
| Feature | Your WebM | The MP4 you get back |
|---|---|---|
| Container | WebM (Matroska-based) | MPEG-4 Part 14 |
| Typical codecs | VP8 / VP9 / AV1 video, Opus audio | H.264 video, AAC audio |
| Plays on | Chrome, Firefox and Edge; hit and miss elsewhere | Every phone, browser, TV and editor |
| File size | Very small at the same quality | Small for the quality |
Before you compress a WebM
A WebM straight out of a browser recorder often has no duration in its header, so players show no length and cannot seek. Converting writes a complete file with a proper duration.
iMovie, the iPhone Photos app and many editing tools will not import WebM at all, so it usually needs converting before it can be edited anywhere else.
compress webm: questions
Will my WebM stay a WebM?
No, it comes back as MP4. The compressor renders H.264 video with AAC audio, which is both smaller than most WebM files and playable everywhere. Use the MP4 to WebM converter afterwards if you need the original container.
Does compression ruin the quality?
At the pre-set level most viewers will not see a difference. Quality only falls apart when you compress hard AND keep a high resolution, which is why the panel pairs a level with a resolution.
Is compressing WebM free?
Yes. Compress and preview free, and a free account downloads the result. Free exports and share pages include a small REQO badge. Go Pro to remove it.
Other presets
Everything else you can do here.
All compress video presets
Crop for a platform
Crop to a ratio
Resize to a resolution
Rotate or flip
Subtitles in another language
Convert a caption file
Need more than compress webm?
REQO is a full browser video editor: record, edit by transcript, caption and export.