Convert MKV to MP4,free and online
MKV files that won't open on a phone, a TV or in an editor. Drop one below, pick the audio track you want and get an MP4 back, usually in seconds and without losing quality. The video never leaves your computer.
Convert an MKV file
This page converts one file at a time, so we took the first one. To convert a whole folder at once, use the free Chrome extension below.
Choose the sound
Reading the file…
Big file: choose where to save it
It will be written straight to your disk, so it doesn't have to fit in browser memory.
Done
A season of episodes in MKV? The free Chrome extension converts a whole folder at once, one click from your toolbar.
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Nothing is uploaded: the video is converted on your own computer.
Why MKV files won't play
MKV is a container that can hold almost anything: several audio tracks, subtitles, sound in AC-3 or DTS. Phones, TVs, editors and upload forms usually expect MP4 instead. Most MKV files already carry H.264 video inside, so turning them into MP4 is a quick rewrap rather than a slow re-encode, and the picture stays exactly the same.
How to convert MKV to MP4
Drop the MKV
Choose the file or drag it into the box above. It is read on your computer.
Pick the sound
If there are several audio tracks, keep the language you want. Turn AC-3 or DTS into AAC when your browser can, so phones play it.
Save the MP4
Small files go to Downloads, big ones are written straight to a folder you pick.
Questions
How do I convert MKV to MP4?
Drop the MKV file into the converter at the top of this page, pick the audio track if there are several, and press Convert. The MP4 lands in your Downloads; big files are written straight to a folder you choose. Nothing is uploaded.
Does converting MKV to MP4 lose quality?
Not when the video inside is H.264, which most MKV files use: the picture is copied into the MP4 as is, so it stays identical and the conversion takes seconds. HEVC video is re-encoded to H.264 so it plays everywhere, which takes longer.
Why does my MP4 play without sound?
Many MKV files carry AC-3 or DTS audio. Browsers and some phones can't play those, so the video looks silent. Tick “Convert the sound to AAC” before converting when your browser can decode the track; otherwise the sound is kept as is and plays in VLC and on most TVs.
Can I choose which audio track to keep?
Yes. If the MKV has several audio tracks, for example two languages or a commentary, the converter lists them and keeps the one you pick.
Are subtitles kept?
No. Subtitle tracks inside the MKV are not carried over into the MP4.
Is it free?
Yes. Free, no sign-up, no watermark. For many files at once there is a free Chrome extension that converts a whole folder.
Have an iPhone video instead? Convert MOV to MP4.
Lots of MKV files?
The free Chrome extension converts a whole folder, no upload.
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