Convert MOV to WebM
Re-encode a QuickTime MOV to WebM with VP9 video and Opus audio. MOV is what a Mac screen recording and an iPhone produce, and WebM is what you want to be serving from a web page — so this conversion sits at the point where something recorded on Apple hardware becomes something a website delivers, which is a very common path for product demos and documentation.
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Add to Chrome — freeDrop your MOV file here, or click to browse
Up to 50 MB. Deleted automatically after 30 minutes.
What it does
- VP9 video and Opus audio
- Screen recordings compress exceptionally well
- Royalty-free, with no patent licensing
- No watermark and no sign-up
How to use MOV to WebM
- 1
Add the MOV
Drop the file in or choose it from your computer, up to 50 MB, no account needed.
- 2
Convert
The video is re-encoded to VP9 and the audio to Opus in a WebM container. Expect this to take longer than converting to MP4.
- 3
Serve it with a fallback
Put the WebM first in your video element and an MP4 second, so every browser gets something it can play.
From Apple hardware to a web page
There is a well-worn path that this conversion sits on. Somebody records a demo with the screen recorder built into macOS, or films something on an iPhone, and the result needs to go onto a product page, into documentation, or into a help article.
What comes out of that hardware is a MOV. What a website wants to serve is something small, because the visitor waits for it and the site pays for it. WebM with VP9 and Opus is generally the smallest sensible answer that browsers play natively.
The step from one to the other is this page. It is not fixing a playback problem — MOV plays fine on the Mac it came from — it is preparing a file for delivery.
Screen recordings are the best case
If the MOV is a screen recording, expect a large reduction, and do not assume something has gone wrong when you see it.
VP9 stores what changed between frames rather than each frame in full, and a screen recording changes very little. A window sits still. A background is one flat color for the entire clip. A cursor moves across a few hundred pixels while everything else is identical to the frame before. The encoder spends almost nothing on all of that, and the file that comes out can be a small fraction of the MOV with no visible difference whatsoever.
Filmed footage does not behave this way. Real-world video has grain, moving light and a camera that never holds perfectly still, so far more of each frame is genuinely new.
How it works
The video is re-encoded to VP9 and the audio to Opus inside a WebM container. Both are full re-encodes, so this takes real time — noticeably longer than converting to MP4, because VP9 is much more expensive to encode.
Always keep a fallback
Serve the WebM and the MP4 together in one video element, WebM first. Browsers play the first source they support, so modern ones take the smaller file and anything older falls back without you doing anything.
Some devices have hardware H.264 decoding and no hardware VP9, which means the MP4 is not only a compatibility fallback but sometimes the better choice for battery life on a phone. Offering both costs a little storage and no complexity.
Examples
A Mac screen recording for documentation
Screen recordings are the ideal input for VP9: large flat areas of unchanging color compress dramatically, so the WebM is often a fraction of the MOV.
A phone clip for a product page
iPhone footage re-encoded for the web, where the file size is paid for by whoever serves it and waited for by whoever visits.
Frequently asked questions
Why convert a MOV to WebM rather than MP4?
Because the destination is a web page rather than a person. MP4 is the right answer when somebody needs to open the file; WebM is the right answer when a browser needs to download it, because VP9 usually delivers the same visible quality in fewer bytes and the format carries no patent licensing. If you are not the one serving the file, convert to MP4 instead.
Do screen recordings really compress that well?
Yes, dramatically, and it is worth knowing before you judge the result. A screen recording is mostly static — a window that does not move, a background that never changes — and VP9 spends almost nothing on parts of the frame that are identical to the last one. A MOV screen recording can become a WebM several times smaller with no visible difference at all.
Will it play on iPhones?
In Safari on recent iOS, yes, and support has improved considerably. It is still the reason to serve an MP4 as a fallback rather than replacing it: some older devices and some hardware decoders handle H.264 only, and a video element with two sources costs nothing and covers all of them.
Why is this slower than converting to MP4?
Because VP9 encoding is far more computationally expensive than H.264. That is the trade for its efficiency — it spends more effort deciding how to represent each frame, and the result is a smaller file. The settings used here are chosen so the conversion completes in reasonable time rather than producing the smallest possible output.