# Convert MOV to WebM

> Convert MOV to WebM online free: iPhone and Mac videos become small VP9 WebM files for websites. Many at once, nothing is uploaded. No sign-up, no watermark.

URL: https://nibbo.org/en/mov-to-webm/

## MOV

MOV is Apple’s QuickTime format: iPhones, iPads, Macs and many cameras record it. Since iOS 11 the video inside is usually HEVC, older clips and “Most Compatible” mode give H.264, and the sound is AAC.

Windows, Android apps and many upload forms still expect MP4, even though the streams inside a MOV are the same ones an MP4 uses.

## MOV to WebM: remux or re-encode

MOV to WebM is always a re-encode: WebM holds VP9 (or VP8, AV1), not the H.264 or HEVC inside the MOV. Your browser’s VP9 encoder does the work, the sound becomes Opus.

At the Original preset a 1080p minute becomes about 45 MB of VP9, usually less than a phone’s MOV. VP9 encoding is slower than playing the video; a 4K clip takes several times its length.

## How it works

1. Drop one or more MOV files: WebM is already selected. Quality, maximum resolution and sound can be changed before you start.
2. Streams that fit WebM are copied; anything else is re-encoded with WebCodecs, or FFmpeg compiled to WebAssembly when the browser can’t.
3. Download each file, or all of them as one ZIP.

## Questions

### Are my videos uploaded?

No. Reading, remuxing and encoding all run in this browser tab. Open DevTools and watch the Network tab while a file converts: no request carries it.

### Why is one file done in seconds and another takes minutes?

A remux only copies the streams, so it runs at disk speed. A re-encode decodes and encodes every frame; FFmpeg in WebAssembly, used when the browser can’t, is slower still.

### How large can a video be?

Up to 3 GB per file for free, and as many files as you like. Remuxes and WebCodecs re-encodes stream from the disk; the FFmpeg path holds the result in memory.

## Related

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- [Convert AVI to MP4](https://nibbo.org/en/avi-to-mp4/)
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- [Convert MOV to GIF](https://nibbo.org/en/mov-to-gif/)
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- [Convert MKV to MP3](https://nibbo.org/en/mkv-to-mp3/)
- [Convert AVI to MP3](https://nibbo.org/en/avi-to-mp3/)
- [MP4 to MP3](https://nibbo.org/en/mp4-to-mp3/)

### Compress video

- [Compress video to a target size](https://nibbo.org/en/compress-video/)
- [Compress MOV video](https://nibbo.org/en/compress-mov/)
- [Compress WebM video](https://nibbo.org/en/compress-webm/)

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