WebM to MP4. Without uploading it anywhere.
Runs in your browser. Your file is processed on this device and never uploaded.
Free for files up to 100 MB. No sign-up, no watermark. Pro removes the limit for $4.99 a month.
Browser screen recorders and many web tools save video as WebM, which iPhones, Premiere, PowerPoint and messaging apps often refuse to open. Convert it to an H.264 MP4 right here. The file is read on your own device and never leaves your browser.
How to convert WebM to MP4
Drop in the WebM file.
Screen recordings, clips saved from websites and exports from browser based recorders all work. Nothing is sent to a server, so even a long recording starts right away.
Click Convert to MP4.
The VP8, VP9 or AV1 video is re-encoded as H.264, and Opus or Vorbis audio becomes AAC, at high quality and the same resolution.
Download the MP4.
It plays on iPhone and Android, imports into Premiere, Final Cut and PowerPoint, and sends on WhatsApp. Too big to send? Run it through the video compressor next.
Why WebM files won't open everywhere
WebM is a video format made for the web. Browsers record and play it natively, which is why screen recorders that run in Chrome or Firefox, and many online tools, save their videos as WebM.
Outside the browser, support is patchy. The iPhone Photos app won't import WebM, video editors such as Premiere Pro don't handle it reliably, and PowerPoint, WhatsApp and many upload forms expect MP4. Converting to MP4 with H.264 video and AAC audio, the most widely supported combination, fixes all of these.
Most online converters upload your file to their server first. Here the conversion runs inside your browser, so a private screen recording, a meeting or a work demo stays on your computer the whole time.
| WebM | MP4 (H.264) | |
|---|---|---|
| Plays in Chrome, Edge and Firefox | Yes | Yes |
| Opens in iPhone Photos | No | Yes |
| Imports into Premiere and PowerPoint | Unreliable | Yes |
| Sends on WhatsApp and most upload forms | Often rejected | Yes |
| Typical video codec | VP8, VP9 or AV1 | H.264 |
Questions about this tool.
Is my WebM file uploaded?
No. The converter runs in your browser and reads the file on your device. The MP4 is created on your computer too, so you can even disconnect after the page loads.
Why did my screen recording save as WebM?
Recorders that run in a browser use the browser's built in recording, and browsers record WebM. Converting afterwards is the usual fix.
Does converting reduce the quality?
The video is re-encoded at high quality and the same resolution, so the difference is very hard to see. The MP4 may be a bit larger than the WebM.
Can I make the MP4 smaller?
Yes. Use the video compressor to pick an exact size in MB, or the WhatsApp, Discord and email pages for their limits.
I only need the sound. Can I get an MP3?
Yes. Use extract audio from video to save the WebM's audio as MP3, M4A or WAV.
It says my browser can't read the video. What now?
Some WebM files use AV1, which older browsers can't decode. Try the latest Chrome or Edge, or the desktop app.
Prefer a desktop app?
The Mac and Windows app works offline and saves results beside your original. It includes 5 free conversions, and Pro unlocks it on up to 3 computers at no extra cost.