Are my WebM files uploaded anywhere?

No. This conversion runs entirely inside your browser, so the file never leaves your device. You can confirm it yourself: open the network tab of your browser's developer tools and convert something. You will see the page load, plus the analytics and advertising the site is paid for with — and nothing carrying your file.

Is converting WebM to MP4 free?

Yes. There is no account, no watermark and no limit on how many files you convert — it runs on your own machine, so it costs us nothing to let you. Files up to 100 MB are handled in the browser.

Does converting WebM to MP4 lose quality?

MP4 is a compressed format, so some data is discarded. At the default setting the difference is not visible; you can raise the quality setting if you need to be certain. Video is re-encoded rather than copied, so some detail is lost even at the highest setting. Subtitle tracks and chapters are not carried over.

Do I need to install anything to open MP4 files?

No installation is needed for the conversion itself — it runs in the browser you already have. Opening the MP4 afterwards needs whatever software normally handles MPEG-4 Video on your device.

WebMtoMP4

Convert WebM to MP4

Up to 100 files at once. Mixed formats are fine.

You can convert WebM to MP4 free and without an account: drop the file above and the MP4 is ready to download in a second or two. The conversion happens inside your own browser, so the file is never uploaded — it works on Windows, Mac, Linux, iPhone and Android, and keeps working with the network switched off.

What WebM and MP4 are for

The royalty-free web video format. Small files, plays in browsers, ignored by most TVs.

The video format that plays everywhere. If in doubt, this is the answer.

How to convert WebM to MP4

Drop your WebM file onto this page, or click to pick one.
Choose MP4 as the target. The conversion runs inside your browser — the file is never uploaded.
Download the finished MP4 file.

WebM vs MP4: what changes

WebM compared with MP4
	WebM	MP4
Full name	WebM Video	MPEG-4 Video
File extension	.webm	.mp4
Media type	video/webm	video/mp4
Compression	Lossy — file size is bought with quality	Lossy — file size is bought with quality

Quality: Some quality is given up for a smaller file. At the default setting the difference is hard to see.
Where it runs: This conversion runs inside your browser. Your file is never uploaded, and it works with the network disconnected.
What can be lost: Video is re-encoded rather than copied, so some detail is lost even at the highest setting. Subtitle tracks and chapters are not carried over.

WebM to MP4: common questions

Are my WebM files uploaded anywhere?: No. This conversion runs entirely inside your browser, so the file never leaves your device. You can confirm it yourself: open the network tab of your browser's developer tools and convert something. You will see the page load, plus the analytics and advertising the site is paid for with — and nothing carrying your file.
Is converting WebM to MP4 free?: Yes. There is no account, no watermark and no limit on how many files you convert — it runs on your own machine, so it costs us nothing to let you. Files up to 100 MB are handled in the browser.
Does converting WebM to MP4 lose quality?: MP4 is a compressed format, so some data is discarded. At the default setting the difference is not visible; you can raise the quality setting if you need to be certain. Video is re-encoded rather than copied, so some detail is lost even at the highest setting. Subtitle tracks and chapters are not carried over.
Do I need to install anything to open MP4 files?: No installation is needed for the conversion itself — it runs in the browser you already have. Opening the MP4 afterwards needs whatever software normally handles MPEG-4 Video on your device.