Convert MKV to MP4 Online for Free
Turn an MKV recording into an MP4 you can play, edit or share.
Drop your MKV file here
or choose a local file or import from a URL
Choose a file to get started
How to convert MKV to MP4
1. Choose the MKV
Select the recording on your device. If it contains several audio tracks, listen to the original and identify what the viewer needs to hear.
2. Set the resolution
Keep Original for a full-size viewing copy. Try 1080p for a smaller version of a 4K recording and check any small labels in the picture.
3. Save the MP4
Select Convert MKV to MP4, preview the result and download it. Open the saved file in the app your recipient will use.
Convert MKV to MP4 from an OBS recording
If an OBS recording plays desktop sound but no microphone, open the audio track menu in a player that supports MKV. Switch tracks during a passage that contains both sounds. If the microphone is on a separate track, prepare a combined mix before converting MKV to MP4 for playback. Retain the separate tracks if you need to adjust their levels later.
| Delivery | What needs to survive | Check before sending |
|---|---|---|
| Client review | A picture and a mix containing every sound the client needs. | Play the downloaded MP4 with the default audio selection. |
| Editing handoff | Separate microphone, application or music tracks for the editor. | Open the master in the editor and solo each required track. |
| Silent screen capture | The full sequence of actions and readable labels. | Check the last action and its result with the sound muted. |
When a player only plays your microphone
A player can switch between two soundtracks without playing them together. Try the audio-track menu at the moment you chose. If one track contains just the microphone and another contains just the desktop, both sounds were recorded. For a client copy, export a mix with both audible from your editing project. This MKV to MP4 converter has no track mixer or language selector. Keep the original MKV for an editor who needs to change the two levels independently.
When can you convert MKV to MP4 without re-encoding?
MKV and MP4 describe how a file holds its streams. H.264 and HEVC describe ways of encoding its pictures. If a destination can already decode the video and audio, changing the container may be enough. This is called remuxing. Copying a compatible video stream into a new container leaves its encoded picture data intact. Changing the filename extension alone does not create that container.
If you recorded the file in OBS and only need a different container, its Remux Recordings command is one route. If the editor rejects the video codec inside the result, another remux will keep that codec. Here the output is H.264 video with AAC audio when the source has a readable sound track. Compatible streams can be reused when the local conversion path allows it. Resizing the picture or changing its codec requires new video encoding.
What Original resolution preserves
When you convert MKV to MP4 with Original selected, the aim is to keep the source dimensions. It does not guarantee an identical file size, a lossless transcode or a copy of every track. A useful comparison for a desktop recording is a small number at the edge of a chart. Pause the MKV and the MP4 at the same point and display them at the same size. Then play a fast scroll to see how moving text looks.
Check subtitles before an MKV to MP4 handoff
If a subtitle disappears when you turn subtitles off in a player, it is being supplied separately from the picture. An MKV can carry text subtitles, styled subtitles or picture-based subtitles. A player may also load a separate SRT file from the recording folder. Seeing words on your screen therefore tells you little about what the recipient will see when you send only the MP4.
To check a handoff, put the downloaded MP4 in a folder by itself. Open it in the destination player and find a line of dialogue you recognise. If the words are already drawn into the source pictures, they remain visible in the converted pictures. For a switchable subtitle track, keep its source separately and prepare the track in the format your recipient can use. This page has no subtitle selection or burn-in control.
To check subtitle sync after an MKV to MP4 conversion, compare the same cue in both files. A subtitle timed for the full recording needs different timestamps if the output is later trimmed. For example, a line at 12:40 in the source appears at 00:10 in a clip starting at 12:30, provided that playback speed and the intervening footage are unchanged.
Frequently asked questions about MKV to MP4 conversion
Can I convert MKV to MP4 online for free without signing up?
Yes. Choose a local MKV, select a resolution and download the MP4 from your browser. The file is processed on your device. You can then send the saved copy through your own review or delivery channel.
Will the export keep every OBS audio track?
The MKV to MP4 converter produces a viewing copy and has no track-mapping controls. Keep the multitrack recording for editing. If viewers need the microphone and desktop sound together, prepare a mix that contains both.
Why does the MP4 play the game sound but not my voice?
Listen to a moment when you spoke in the original MKV and switch audio tracks in your player. If the commentary is on another track, use your recording or editing software to make a combined mix. If the microphone was never captured, converting the file cannot restore the speech.
Why does my editor still reject the file after a remux?
Check the codec your editor expects. A remux can leave HEVC or another video codec exactly as it was in the MKV. If the editor needs H.264, convert from the original with that target, then import the downloaded file and check both picture and sound.
Can I keep my source at 4K?
Choose Original in the MKV to MP4 converter, then compare the saved dimensions with the source. Keeping a 4K frame does not guarantee that every video packet will be copied.
Will the MP4 take up less space?
It depends on the source codec, duration and amount of data used for the output. A container change alone usually saves little. If a delivery service has a specific size limit, measure the download and use the video compressor to prepare a smaller copy if needed.
Can viewers switch the subtitles on and off?
The MKV to MP4 preset does not offer subtitle track selection. For switchable captions, retain the source track. If you have an SRT, the related subtitle tool can add a selectable text track to a video.
Can I import a link to a shared folder?
A sharing page often opens a player or asks for an account. Download the original MKV and use the file picker. To import by URL you need a direct HTTPS media link that the browser has permission to read.
What if the MKV has no audio at all?
A silent video can be converted when its video track is readable. Open the source in a player and try a few different scenes. If the recording contains no microphone or application audio, the new MP4 will not add a soundtrack.
Can I specify an HDR delivery profile?
If the recipient requires specific HDR characteristics, keep the original and use a workflow with explicit colour-management and export controls. This page offers a resolution setting. It does not provide a tone-mapping control or promise to retain HDR metadata.
Why does a long recording stop processing?
An MKV to MP4 export needs enough working memory for the recording. Close other memory-intensive applications and keep the tab open. A short excerpt can help establish whether the streams are readable before you try the full source again.
Should I delete the MKV after making the MP4?
Keep it until you know which tracks, captions and editing options you will need. A viewing copy may contain just one mix, while the MKV still contains the original microphone and desktop tracks. The original recording is the best starting point for those changes.