WebM to MP4

Convert WebM to MP4 in your browser: screen recordings and web videos become MP4 that plays everywhere. Free, no sign-up, nothing uploaded.

Runs in your browser. Your files are never uploaded. How it works

WebM to MP4 converts WebM videos (from screen recorders, browsers and websites) into MP4 so they open in every player, editor and phone. It runs in your browser and adds no watermark.

Where WebM files come from

Source Why convert
Browser screen recorders Editors and slides want MP4
Downloaded web videos Phones and TVs play MP4
Video calls recorded in the browser Easier to share as MP4

Screen recorders that run in a browser, such as extensions and recording websites, usually write WebM (VP8 or VP9 video, often with Opus sound). That file plays in the browser that made it, but:

  • iMovie, many older video editors and the default players on some laptops do not open WebM
  • iPhones before iOS 15 cannot play it, and some Android gallery apps still skip it
  • Older versions of PowerPoint and many school or office setups do not play WebM; MP4 plays in all of them
  • USB playback on a TV almost always wants MP4

Converting once, on your computer, avoids sending a file that the other person cannot open.

What the conversion does

Many MP4 players do not support the WebM codecs (VP8, VP9, Opus), so the video is re-encoded as H.264 and the sound as AAC, at the bitrate of the original. The picture size and length stay the same. On a recent computer this is usually a few seconds per minute of video; keep the tab open until it is done.

The result is an MP4 with no watermark. Chrome, Edge and Safari on a recent computer give the most compatible file.

Tips for screen recordings

  • Cut first. A 20-minute recording of a whole meeting is slow to convert and large to send. Use Trim Video to keep the few minutes that matter, then convert that clip.
  • Cursor and UI are sharp. Screen content compresses well. If the MP4 is still huge, Video Compressor at 50% smaller rarely hurts a recording of slides or a desktop.
  • System audio. If the WebM has no sound (many browser recorders capture the screen only), the MP4 will be silent too. That is expected.
  • High frame-rate game captures take longer. Let the conversion finish; cancelling leaves nothing to download.

Drop the .webm file, leave Convert to on MP4, click Convert, then download. Nothing is uploaded.

Frequently asked questions

Why won't my WebM play?

WebM is a web format; some phones, iPhones before iOS 15, Windows apps and video editors do not open it. MP4 plays everywhere.

Will the video look worse?

It is re-encoded at the bitrate of the original, so it looks the same for normal viewing.

Is the WebM uploaded?

No. The file is processed in your browser, on your device, and never sent anywhere.

Where do WebM files come from?

Browser screen recorders (Chrome, Edge, Firefox), some meeting tools, and downloads from websites. If the file ends in .webm, this page will convert it.

Can I convert WebM to MOV instead?

Yes. Change Convert to from MP4 to MOV if you need a file for iMovie or Final Cut. MP4 is still the better default for sharing.

More ways to use Video Converter

Related tools

Add Music to VideoPut a song or any audio on a video, under the original sound or instead of it. Nothing is uploaded.Add Subtitles to VideoBurn subtitles from an SRT or VTT file permanently into a video, with a live preview. Nothing is uploaded.Resize VideoChange a video's size or shape (square, vertical, landscape), filling the space with blur or bars. Nothing is uploaded.Screen RecorderRecord a screen, window or tab with microphone and tab sound. No watermark, no time limit.Trim VideoCut the start and end off a video and keep the part you need. Runs in your browser, nothing is uploaded.Video CompressorMake a video smaller, to a size you choose or by a percentage. Runs in your browser, nothing is uploaded.