WebM to MP4 Converter

About this converter

WebM is the open, royalty-free format built for the web - it uses VP8, VP9, or AV1 video with Opus or Vorbis audio. It is excellent for streaming and websites, but it is a poor fit elsewhere: many video editors, older iPhones, and some TVs will not open a WebM at all.

Converting WebM to MP4 swaps those open codecs for H.264, the format every device and editing program understands. Because VP9/AV1 are not MP4-compatible, this is always a re-encode rather than a quick repackage.

One thing to expect: H.264 is less efficient than VP9 or AV1, so the resulting MP4 can be a little larger than the WebM it came from - the trade you make for universal playback.

WebM to MP4: good to know

• Always a re-encode: WebM's VP8/VP9/AV1 video cannot be copied into MP4, so the file is converted frame by frame.
• Slightly larger output is normal, because H.264 compresses less tightly than modern WebM codecs.
• Great for getting screen recordings and downloaded clips into iMovie, Premiere, or a phone's photo library.

How it works

1. Drop your file(s) in the box above (or click to browse).
2. Make sure MP4 is selected as the output.
3. Click Convert, then Download your file.

Frequently asked questions

How do I convert WebM to MP4?

Drop your WebM file above, make sure MP4 is selected, and click Convert, then Download. Everything runs locally - the file is never uploaded.

Why won't my WebM play in my video editor?

Most editors and many devices do not support WebM's VP9/AV1 codecs. Converting to an H.264 MP4 produces a file they can open and edit normally.

Will the MP4 be larger than the WebM?

Often slightly, yes. VP9 and AV1 compress more efficiently than H.264, so re-encoding to MP4 can increase the file size a little. That is the cost of universal compatibility.

Does converting WebM to MP4 lose quality?

It is a re-encode, so technically yes, but at the High quality setting the difference is hard to see. Use a higher quality if you plan to edit the result further.

Is it really free and private?

Yes - 5 conversions a day with files up to 1 GB, no account, and nothing leaves your device. Pro ($5/month) lifts both limits.

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