CloudConverterConvert WebM to MP4 when a video will not play on your phone, will not import into your editor, or a platform refuses the upload. MP4 is the most widely supported video format.
WebM vs MP4: what changes
WebM is an open format made for the web, often used by screen recorders and browser downloads. MP4 is supported by nearly every phone, TV, editor and social platform. The conversion re-encodes the video, so it takes longer than a simple file rename and the result can differ slightly in size.
When to convert WebM to MP4
Use it for screen recordings and downloaded clips that need to play on iPhone, open in a video editor, or upload to a service that only accepts MP4.
Before you convert
Videos are re-encoded, so longer or larger files take more time. Output is limited to 1920 pixels on the longest side, so 4K videos are scaled down to 1080p. Keep the original WebM if you need the full resolution.
Tips for converting WebM to MP4
Screen recordings from the browser are a common source of WebM files. If the MP4 is for upload to a social platform, check the platform's file size limit before sending. Very long videos take longer to convert, and a conversion that runs too long is stopped.
Convert WebM to MP4 on any device
On a phone, save the WebM, open this page, tap the upload box and choose the video from your gallery or Files app. On Windows and Mac, drag the .webm file onto the box. When the conversion ends, download the MP4 and open it in any player or editor.
Frequently asked questions
Why won't my WebM play on my iPhone or in my editor?
Not every phone, TV or editor supports WebM. MP4 is supported almost everywhere, so converting solves most playback and import problems.
Will the MP4 be larger than the WebM?
Often a little larger, but it depends on the video. The difference is rarely dramatic.
Does the MP4 keep the sound?
Yes. The audio track is converted along with the video.
What is the maximum file size?
200 MB per file.
Will the video quality change?
The video is re-encoded, so small differences are possible, but for normal viewing most people will not notice.
Is it free to convert WebM to MP4?
Yes. It is free, with no sign-up and no watermark.
Are my files kept after conversion?
No. Uploaded files are processed and deleted after your download. We do not keep a library of your files.
Is there a file size limit?
Uploads are capped at 200 MB per file.