Are my M4V 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 M4V to MKV 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 M4V to MKV lose quality?

MKV 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 MKV files?

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

M4VtoMKV

Convert M4V to MKV

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

You can convert M4V to MKV free and without an account: drop the file above and the MKV 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 M4V and MKV are for

Apple's MP4 variant. Identical in practice unless the file carries copy protection.

An open container that holds anything — several audio tracks, subtitles, chapters. Weak on hardware players.

How to convert M4V to MKV

Drop your M4V file onto this page, or click to pick one.
Choose MKV as the target. The conversion runs inside your browser — the file is never uploaded.
Download the finished MKV file.

M4V vs MKV: what changes

M4V compared with MKV
	M4V	MKV
Full name	iTunes Video	Matroska Video
File extension	.m4v	.mkv
Media type	video/x-m4v	video/x-matroska
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.

M4V to MKV: common questions

Are my M4V 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 M4V to MKV 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 M4V to MKV lose quality?: MKV 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 MKV files?: No installation is needed for the conversion itself — it runs in the browser you already have. Opening the MKV afterwards needs whatever software normally handles Matroska Video on your device.