How to Convert WebM to MP4 for Free (No Upload, Any Device)

To convert WebM to MP4, open the free WebM to MP4 converter, drop your .webm file in, pick a quality and click Convert. The MP4 is created inside your browser, so the video is never uploaded, and it plays on iPhones, Windows, TVs and in video editors.

Below you will find why WebM files cause problems, what the converter changes, how to choose a quality setting and how to fix the most common errors.

What is a WebM file?

WebM is an open video format created by Google for the web. A WebM file usually holds VP8, VP9 or AV1 video and Opus or Vorbis audio. Browsers play it well, which is why you meet it so often:

• Screen recordings made with browser based recorders and many extensions are saved as WebM, because that is what the browser's built in recorder produces.
• Downloaded clips from websites are often WebM, since sites serve it to save bandwidth.
• Video messages and GIF replacements on some platforms are WebM behind the scenes.

WebM vs MP4: why convert?

WebM is efficient, but its support outside the browser is patchy. MP4 with H.264 video is the safest format there is.

	WebM	MP4 (H.264 + AAC)
Plays in Chrome, Firefox, Edge	Yes	Yes
Plays on iPhone Photos and older iOS	Often not	Yes
Opens in editors and slide decks	Often not	Yes
Accepted by upload forms and some social apps	Sometimes	Almost always
Typical use	Web playback	Everything

If you need to edit the clip, put it in a presentation, send it to an iPhone user or upload it to a form, convert WebM to MP4 first.

How to convert WebM to MP4 (step by step)

1. Open the WebM to MP4 converter in Chrome or Edge for the fastest result.
2. Drop your .webm file onto the page. The tool reads it on your device and shows duration, resolution and codecs.
3. Check the line under the file: it tells you what will be copied and what will be re encoded.
4. Choose High quality (close to the original) or Balanced (smaller file).
5. Click Convert and download the MP4. The result shows the size before and after.

There is no sign up, no watermark and no server size limit, because nothing is uploaded.

Does converting WebM to MP4 lose quality?

Usually a little, and here is why. Most WebM files contain VP8 or VP9 video, which does not belong in a widely playable MP4. The converter therefore decodes the video and encodes it again as H.264 with your browser's hardware encoder. Every re encode is lossy in principle, but at the High quality setting the difference is very hard to see, especially for screen recordings with text and flat colours.

There is one exception: some browser recorders save H.264 video inside a WebM file. The converter spots this and copies the video into the MP4 without touching it. That conversion takes seconds and loses nothing.

Audio follows the same logic. Opus or Vorbis audio is converted to AAC at 160 kbps (High quality) or 128 kbps (Balanced), which is plenty for voice overs, meetings and music.

Which quality setting should you choose?

Your video	Best setting	Why
Screen recording or tutorial	Balanced	Text stays sharp; the file is much smaller
Gameplay or fast motion	High quality	Motion needs more bits to avoid blocky frames
Clip for editing later	High quality	Leaves headroom for a second export
Clip to send by chat or email	Balanced	Smaller file; compress further if needed

If the MP4 is still too big to send, run it through the video compressor, which can aim for a target size.

Why screen recordings from the browser are worth converting

WebM files made by the browser's built in recorder are written as a live stream. As a result, many of them are saved without a proper duration or seek index: the player shows no total length and the progress bar will not let you jump ahead. Converting to MP4 writes a complete index, so the finished file shows its length and seeks instantly. This alone is a good reason to convert recordings you plan to share.

Browser converter, VLC or HandBrake?

All three can turn WebM into MP4. The right one depends on how many files you have and where you are working.

Method	Install needed	Uploads your file	Best for
WoowTools in the browser	No	No	One or a few files, work computers, private recordings
VLC (Convert/Save)	Yes	No	People who already use VLC as their player
HandBrake	Yes	No	Big batches and fine control over every encoder setting
Typical upload converters	No	Yes	Small, non private clips only

For a single screen recording, the browser route is the quickest: no setup, no profiles to pick and no file sent anywhere. If you convert dozens of files every week, a desktop app with a queue such as HandBrake saves time. Avoid upload converters for meetings, client calls or anything personal, because the file sits on someone else's server while it converts.

Common WebM to MP4 problems and fixes

Problem	Cause	Fix
"This browser cannot encode H.264"	No H.264 encoder in this browser	Use the latest Chrome or Edge
MP4 has no sound	The audio could not be converted in this browser	The tool tells you; retry in Chrome or Edge
Conversion is slow	Long or 4K clip being re encoded	Plug in the laptop and close heavy tabs
MP4 larger than the WebM	VP9 is more efficient than H.264	Choose Balanced or compress afterwards

Related tools

Need only the audio of a recording, for a podcast or transcript? Use extract audio from video. Got an iPhone clip instead? The MOV to MP4 converter handles HEVC videos the same private way. For the background on these formats, see how to convert MOV to MP4.

Ready? Open the free WebM to MP4 converter and drop in your file. It never leaves your device.

Frequently asked questions

Can I convert WebM to MP4 without losing quality?

Only when the WebM already holds H.264 video, which some browser recorders produce; the converter then copies it losslessly. VP8 and VP9 video must be re encoded to H.264, and the High quality setting keeps the difference very hard to see.

Why won't a WebM file play on my iPhone?

iPhones and the Photos app have limited WebM support, especially on older iOS versions. Converting the file to an H.264 MP4 makes it play on every iPhone.

Is it safe to convert WebM to MP4 online?

WoowTools converts the file inside your browser, so it is never uploaded to a server. That keeps private meetings and screen recordings on your own device.

Why is my converted MP4 bigger than the WebM?

VP9, the codec in most WebM files, compresses more efficiently than H.264. Choose the Balanced setting or run the MP4 through a video compressor if you need a smaller file.

Can VLC convert WebM to MP4?

Yes, VLC's Convert/Save option can do it, but it needs installing and several settings. A browser converter is quicker for one file and works on computers where you cannot install software.