Convert to and from WebM, free.
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.
Convert something else to WebM
Pick what you have. Each page opens the editor with WebM already selected as the output.
Convert WebM to something else
Pick where it is going. Most editing software, phones and TVs will not open a WebM file.
WebM next to the formats it converts with
Where each one plays, what it is for and how heavy it is, so you can pick the target before you open a converter.
WebM
MP4
MOV
AVI
MKV
GIF
MP3
WAV
| Format | Best for | Plays on | File size |
|---|---|---|---|
| WebM | Web embeds and browser recordings | Chrome, Firefox and Edge; hit and miss elsewhere | Very small at the same quality |
| MP4 | Sharing anywhere, uploads, web embeds | Every phone, browser, TV and editor | Small for the quality |
| MOV | Editing on a Mac, footage straight off an iPhone | macOS and iOS natively, patchy elsewhere | Large, especially ProRes |
| AVI | Opening archive footage from the 2000s | Desktop players with the right codec pack | Very large for the quality |
| MKV | Archiving with multiple audio and subtitle tracks | VLC and desktop players; rarely anywhere else | Depends entirely on the codec inside |
| GIF | Short silent loops in docs, chat and email | Everywhere an image can be shown | Huge for anything over a few seconds |
| MP3 | Podcasts, voice notes, music you need to send | Every device made in the last 25 years | Roughly a tenth of uncompressed audio |
| WAV | Editing, mastering, voiceover work | Every desktop and audio tool; large for phones | About 10 MB per minute in stereo |
What WebM actually is
WebM (Matroska-based)
VP8 / VP9 / AV1 video, Opus audio
Web embeds and browser recordings
Chrome, Firefox and Edge; hit and miss elsewhere
Very small at the same quality
Streams natively in Chrome, Firefox and Edge with no plugin.
VP9 delivers smaller files than H.264 at the same visual quality, which cuts bandwidth on a busy page.
Most editing software, phones and TVs will not open a WebM file.
Social platforms and messaging apps frequently reject the extension outright.
Safari and older Apple devices handle WebM inconsistently.
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.
Questions about WebM
What is a WebM file?
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. It is the WebM (Matroska-based) container, usually holding VP8 / VP9 / AV1 video, Opus audio.
Is converting WebM free?
Yes. Convert 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. Nothing is installed.
Will converting to WebM lose quality?
Some, whenever the codec changes: every re-encode discards detail. Where the container can simply be rewritten around the existing streams it is lossless, and where it cannot the default settings are chosen so the loss is not visible at normal viewing size.
Other formats
Convert it, then keep editing.
Every converter opens the full editor, so you can trim, caption and share without uploading the file twice.