WebM to MP4 converter

Convert WebM video to MP4 in your browser. When the codec fits, only the container changes, so it takes seconds and the quality stays the same.

    Drop WebM files here or choose files.

    • 500MB per file. Up to 10 minutes when only the container changes, 3 minutes when re-encoding. Up to 5 files at a time
    • The first time you use it, the browser downloads the video engine (about 31MB)

    Auto skips re-encoding when the source can go into the new format as is, which is fast and keeps the quality intact. Otherwise it re-encodes at normal quality. Light reduces the file size at some cost in picture quality.

    For vertical video this refers to the shorter side. Choosing a size smaller than the original forces a slower re-encode. The tool never upscales.

    Files never leave this device. Privacy policy

    Result

    Upload a WebM video and click Convert. The MP4 file will appear here.

    What to do next

    MP4 to WebM converter

    Convert a MP4 video back to WebM.

    Compress a video

    Shrink the video to fit iMessage, Gmail or Discord upload limits.

    Trim a video

    If a video is too long to convert, cut out the part you need first. Quality stays the same.

    How it works

    Choose a WebM video and click Convert to save it as MP4. MP4 (H.264) is the most common video format and plays on phones, computers, TVs, messaging apps and YouTube.

    With quality set to Auto, the tool first checks the codec inside the video. If MP4 can hold it as is, it swaps only the container without re-encoding. That takes a few seconds and the quality is unchanged. If the codec does not fit, the tool re-encodes and tells you below the result which method it used. Several files convert one after another.

    Things to know

    If the source is H.265 (HEVC), Auto copies it as is, which is fast, but older Windows PCs and TVs may not play it. If that happens, convert again with Normal.

    Re-encoding processes every frame on your device, so it is slow. That is why the limit is 10 minutes when only the container changes and 3 minutes when re-encoding. 4K video is reduced to 1080p when it has to be re-encoded.

    Frequently asked questions

    Does it work with screen recordings saved as WebM?

    Yes. WebM files from browsers and screen recorders use VP8 or VP9, which MP4 and MOV cannot hold as is, so the tool re-encodes to H.264. To keep that workable on your device, it accepts videos up to 3 minutes. For longer ones, cut out the part you need with Trim a video first.

    Where will the converted MP4 play?

    An MP4 with H.264 inside plays on iPhone, Android, Windows, Mac, smart TVs, messaging apps and YouTube. The one exception is when the source was H.265 (HEVC) and was copied as is. That may not open in the built-in Windows apps, and the tool notes this below the result.

    Why does it take so long? Does it work on a phone?

    The video is processed on your device, not on a server. When only the container changes, it takes a few seconds. When the video has to be re-encoded, it can take several times the length of the video depending on your hardware. It works on a phone but much more slowly, and it stops if the screen turns off or you switch apps. For long videos, use Chrome or Edge on a computer.

    Are my files uploaded to a server?

    No. The conversion runs entirely in this browser, and the file never leaves your device. The only download is the conversion engine, once. The result disappears when you close the page, so use the save button to keep it.

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