WebM to MP4 Converter
Turn WebM recordings and clips into MP4 that plays on iPhone, Mac, Windows and in social apps, and opens in video editors. Free, with no account and no watermark.
Output: MP4 with H.264 video and AAC audio, the most widely supported combination.
Need more changes? Continue in the full editor after downloading or processing the converted file.
How to convert WebM to MP4
The converter re-encodes the video into a standard MP4 file. You do not need to choose a codec, quality or resolution.
Step-by-step
- Choose a WebM file or drag it onto the upload area.
- Wait for the upload to finish, then click Convert to MP4.
- Wait while the video is converted. Long or 4K videos take longer.
- Download the MP4 and play, edit or upload it where the WebM did not work.
What you get
The result is built for compatibility rather than for the smallest possible size:
- H.264 video with 8-bit 4:2:0 color, converted from VP8, VP9 or AV1. Practically every phone, computer, TV and browser can play it.
- AAC audio, the standard audio format for MP4, converted from Opus or Vorbis.
- A correct duration. Browser recordings often have no length stored in the file; the MP4 has a proper duration, so players show the length and you can skip through it.
- The original resolution and frame rate. An odd width or height is rounded down by one pixel, because H.264 needs even dimensions.
- Fast start for the web: the MP4 can start playing in a browser before it has fully downloaded.
Why a WebM file may not play
WebM is an open format made for browsers: it holds VP8, VP9 or AV1 video with Opus or Vorbis audio. Browsers play it well, but much other software does not. QuickTime Player, the iPhone Photos app, iMovie and Final Cut Pro do not open WebM, many presentation programs and video editors leave it off their import lists, and upload forms often accept only MP4 or MOV. For editor-specific steps, see this guide: How to Use WebM in Premiere Pro, DaVinci Resolve and iMovie.
Sometimes the file opens but only partly works: the picture plays without sound because the player has no Opus decoder, or a TV or older phone cannot decode VP9 or AV1 at all. Because WebM and MP4 normally use different codecs, renaming the file does not help. The video and audio have to be re-encoded, which is what this converter does.
Screen and browser recordings in WebM
Most WebM files people need to convert are recordings made in a browser: online screen and webcam recorders, video calls and web apps save WebM because that is what browsers record natively. Such files often have no duration in their header, so a player shows the length as unknown, the progress bar does not move, or skipping forward fails.
Converting rebuilds the file with a correct duration and index, so the MP4 can be played, skipped through and imported into an editor like any camera video. Screen recordings often contain small text, so check that it still reads clearly in the result.
When to convert WebM to MP4
Convert when the WebM has to work outside a browser:
- Playing on an iPhone, iPad, Mac, TV or player that does not open the file or plays it without sound.
- Uploading to a social app, website, LMS or online form that accepts only MP4.
- Editing in iMovie, Final Cut Pro or other software that does not import WebM, or adding the video to a presentation.
- Sending a screen recording to someone in a messaging app that does not play WebM as a video.
Quality, file size and limits
Do not expect a smaller file: VP9 and AV1 are very efficient, so the H.264 version of the same video is often larger. If the result is too large to share, run it through the video compressor.
Files can be up to 200 MB. Transparency is not kept, because MP4 with H.264 does not support an alpha channel: transparent areas of a WebM animation or sticker become a solid color. If the WebM has several audio tracks, the MP4 gets the default one, usually the first. For longer videos, use the full Deus Video online editor: it accepts files up to 1 GB, with no size limit on the Maxi plan, and exports MP4.
Compress, trim or convert the MP4
MP4 to WebM Converter
Turn an MP4 into a WebM with VP9 and Opus for websites and browsers.
Compress Video
Make the MP4 smaller if it came out larger than the WebM.
Trim Video
Cut the start and end of a screen recording before you share it.
Convert Video Format
Convert to MOV, MKV, AVI or another format instead of MP4.
Need to Edit Your Video?
Continue with trimming, resizing, cropping, text, subtitles, audio, and other edits in the full editor.
Learn more about WebM and MP4
Frequently Asked Questions
Common questions about converting WebM files to MP4.
Is the WebM to MP4 converter free?
Yes. It is free, you do not need an account, and the MP4 has no watermark.
Will converting WebM to MP4 reduce quality?
The video is re-encoded, so it is not lossless, but the settings keep the original resolution and frame rate and aim to keep the difference hard to see. Convert from the original WebM once rather than converting an already converted file again.
Why is the MP4 larger than the WebM?
WebM usually stores video in VP9 or AV1, which compress better than H.264. MP4 with H.264 needs more data for the same picture, but it plays almost everywhere. If size matters, compress the MP4 afterwards.
My screen recording shows no duration and I cannot skip through it. Will converting fix it?
Yes. Browser recordings often have no duration stored in the file. The converted MP4 has a correct duration, so players show its length and you can skip to any point.
Can I keep the transparent background of a WebM?
No. MP4 with H.264 has no alpha channel, so transparent areas become a solid color. To keep transparency, use the WebM itself where it is supported, or a format with an alpha channel such as ProRes 4444 in MOV.
Is there a file size limit?
Yes, files can be up to 200 MB. If a recording is larger, trim it first and convert only the part you need.