How do I change a WebM file to MP4?

Drop the .webm on this page and click Convert to MP4. Your computer re-encodes the video to H.264 and the audio to AAC, and the MP4 downloads under the same file name.

How can I convert WebM files to MP4 for free?

Use the converter above. There is no fee, no account and no watermark, and no limit on how many files you convert; the only cost is the time your computer spends encoding.

Can VLC Player convert WebM to MP4?

Yes. Open Media, then Convert / Save, add the file and pick the Video - H.264 + MP3 (MP4) profile. VLC re-encodes too, and its audio comes out as MP3 rather than AAC. If you only need to watch the clip, VLC plays WebM as it is.

Is WebM better quality than MP4?

Neither container decides quality; the codec and bitrate do, and both can look excellent. Converting WebM to MP4 can't add detail the recording never had, so choose High when the picture matters most.

Will the converted MP4 play on my iPhone?

For VP8 and VP9 files, yes in normal use: they come out as H.264 with AAC audio, which iPhone and iPad play natively. If the WebM held AV1, the MP4 keeps AV1, and older iPhones may not play it.

Why is WebM to MP4 slower than other conversions?

Because the picture has to be rebuilt. An MKV often only needs a new container, but VP8 and VP9 must be decoded and encoded as H.264, and the browser converter uses one CPU core. Our 6-second 720p VP9 clip took about 19 seconds.

Does Fast Copy work on WebM files?

Only partly. It still re-encodes VP8 and VP9 video with your saved Quality setting and converts the audio to AAC; only AV1 video is copied. Choose Re-encode when you want to pick the quality or a lower resolution.

Can I run WebM to MP4 on a whole folder at once?

Not here: files go one at a time, though the number you can do is unlimited. For dozens of recordings, a one-line FFmpeg loop on the command line can work through a whole folder.

Is my screen recording uploaded anywhere?

No. The page sends the converter program to your browser, and the recording is read and encoded right there. Cloudflare, which hosts the site, and jsDelivr, which serves the converter, see an ordinary page visit, never the file.

WebM to MP4

WebM to MP4 for screen recordings and web clips your iPhone won't open. Your file is converted on your own device and is never uploaded to our servers.

Free & unlimited
No sign-up
Files never uploaded
No watermark
Up to 2 GB per file

How to convert WebM to MP4

Three steps and nothing to install. Plan for a real encode: WebM video has to be rebuilt as H.264.

1
Choose the .webm file
Drop it on the page or click to browse. Picking only reads the file; its size, duration and resolution appear before any work starts.
2
Pick Fast Copy or Re-encode
VP8 and VP9 video turns into H.264 in both modes. Fast Copy uses your saved Quality setting, Medium unless you changed it. Re-encode lets you choose High, Medium or Small file and scale down to 1080p, 720p or 480p.
3
Convert and save the MP4
A progress bar runs while your computer does the encoding. The download keeps the original name with .mp4 at the end, and the result screen compares the old and new size.

Why use this WebM to MP4 converter

It tells you what really happens to the file, including the slow part.

H.264 and AAC, the pair MP4 players expect

Plenty of players that open MP4, from the iPhone Photos app to PowerPoint, choke on VP9 video or Opus sound. The output is H.264 with AAC at 192 kbps, built for them rather than just renamed.

Straight about speed

Decoding VP9 in a browser is slow work. Our 6-second 720p VP9 test clip took about 19 seconds, roughly three times its length, in Chrome on an Apple Silicon laptop.

No upload for long recordings

A long meeting or tutorial capture never has to crawl up to a server first. The tab reads it from your disk, and encoding begins the moment you click Convert.

You decide the file size

High (CRF 18) keeps the most detail, and Small file (CRF 28) shrinks the clip for chat apps. Our 387 KB VP9 test clip came out as a 184 KB MP4 at Medium.

Index at the front

The MP4 is saved with faststart, its index placed before the video data. A web page or player can start it without waiting for the last byte.

Ways to convert WebM to MP4, side by side

To get H.264, every route here has to re-encode VP9 video. They differ in where the file goes and who does the work.

	This converter	Upload-based converters	HandBrake	VLC Convert / Save
File leaves your device	No	Yes, held on their servers for as long as the service decides	No	No
Install	None, it runs in a browser tab	None	Desktop app	Desktop app
Video comes out as	H.264 (AV1 is copied as AV1)	Set by the site's options	Set by the preset you choose	H.264 with the MP4 profile
Audio comes out as	AAC 192 kbps	Set by the site's options	Set by the preset	MP3 with that profile
Where the time goes	Encoding on your device	Upload, queue and download	Encoding on your computer	Encoding on your computer
File size	About 2 GB per file	Caps depend on the service	Limited by your computer	Limited by your computer
Cost	Free, no sign-up	Depends on the service	Free, open source	Free, open source

WebM clips that usually need to become MP4

WebM is the web's own format, so it piles up from recorders, chats and downloads.

Browser screen recordings

Chrome extensions and Loom-style recorders often save WebM. Convert a product demo or bug report before you send it to someone on a Mac or a phone.

Discord and Telegram saves

Clips saved from chats are often WebM with Opus sound. As MP4 they sit in a camera roll and go out in a WhatsApp message like any phone video.

Downloaded web video

Sites that stream HTML5 video often serve WebM. An MP4 copy is easier to keep next to your phone videos and to pass on to people who aren't technical.

iPhone and iPad

Photos and QuickTime Player turn most WebM files away. The H.264 version imports and plays there like a clip you shot yourself.

Training decks

PowerPoint and Keynote take MP4 more reliably than WebM. Convert a screen capture before you embed it in a slide.

iMovie and Final Cut

Apple's editors don't import WebM. Bring in the H.264 MP4 and cut it like any other footage.

What changes inside a WebM when it becomes MP4

A WebM file usually holds VP8 or VP9 video with Opus or Vorbis audio. The players people use with MP4 expect H.264 and AAC instead. So the video is decoded frame by frame and encoded again as H.264, and each audio track becomes AAC at 192 kbps. That is why Fast Copy can't stay fast on this format, and the result screen says the video had to be re-encoded.

A re-encode is never lossless, so the Quality setting matters: High keeps the most detail, Small file trades detail for size. WebVTT subtitles, rare in WebM, are kept as soft subtitles you switch on in the player.

Some newer WebM files carry AV1 video. That stream is copied into the MP4 as it is, with no re-encode, but this converter has no AV1 decoder and can't turn AV1 into H.264. Older phones and TVs may not play the AV1 MP4.

Mistakes to avoid when you convert WebM to MP4

Mistake: Renaming video.webm to video.mp4.
Do this instead: The name changes, but the VP9 video and Opus audio inside stay the same, so the player that refused it still will. Convert it so the streams are rebuilt as H.264 and AAC.
Mistake: Expecting an hour-long recording to finish in seconds.
Do this instead: VP9 has to be decoded and encoded again. Our short VP9 test ran at about three times the clip's length, so start long files when you can leave the tab open.
Mistake: Sending an AV1 WebM to an older device.
Do this instead: AV1 video is copied, not converted, and older phones and TVs may lack an AV1 decoder. Check the MP4 on that device; if it fails, use a desktop converter that can decode AV1.
Mistake: Loading a recording well over 2 GB.
Do this instead: The browser runs out of memory around that size. FFmpeg or HandBrake on a computer can handle files that large.

Privacy, cost and limits

Your recording stays on your computer

Screen recordings often show inboxes, dashboards or customer data. Here the WebM to MP4 encode runs inside the tab, so no copy ends up on someone else's server.

Free, as many files as you like

No account, no watermark and no cap on the number of conversions. Files go one at a time; there is no batch queue.

Up to about 2 GB per file

That is the practical memory ceiling of WebAssembly in a browser. In our tests a 1.6 GB MKV converted fine and a 2.1 GB file ran out of memory.

One 32 MB download first

The first conversion fetches the converter, FFmpeg 5.1.4 compiled to WebAssembly, from jsDelivr. After that it loads from your browser cache.