Is MOV to WebM lossless?

No. WebM needs different codecs than MOV, so the video and audio are re-encoded.

Why does my iPhone MOV fail?

iPhones record HEVC by default. Chrome and Firefox often can't decode it; try Safari, or convert it with HEVC to MP4 first.

MOV to WebM

Convert a MOV video to WebM for the web. Processing stays on your device.

Files stay on your device

Drop a file to convert

See its format, then choose an output.

Any media file this browser’s engine can read.

How to convert MOV to WebM online

Open a QuickTime MOV, such as an iPhone or screen recording, and export a WebM for a website or web app. The MOV to WebM converter re-encodes the video to a WebM codec and the audio to Opus in your browser, without uploading the file.

Step 1
Choose your MOV
Pick a file or drop it into the converter above.
Step 2
Keep WebM
WebM is selected; choose another format if you need one.
Step 3
Download the WebM
Save the WebM when the conversion finishes.

What to expect

Supported inputs: MOV files, including iPhone and QuickTime recordings, and other readable video files.
What happens: Video is re-encoded to VP9, AV1, or VP8, whichever this browser can encode, and audio to Opus. Extra tracks this browser can't read, such as spatial audio, may be left out.
Limits: An HEVC MOV, the iPhone default, needs a browser that can decode HEVC, such as Safari. Re-encoding takes longer than copying.

Private by design

Your video stays on your device

Mastershot processes your file locally in this browser. It does not need to be uploaded to a server, and you do not need an account to use the tool.

No upload
No signup
No watermark