Video Compressor
Reduces video file size with adjustable quality and resolution controls.
MKV to MP4 Converter
Turn an OBS recording or Matroska file into an MP4 you can edit, upload, and play anywhere.
- 100% free
- No signup needed
- Browser-based
Why use Jupitrr's MKV to MP4 converter?
Built for OBS recordings
H.264 MKV files are repackaged into MP4 without re-encoding, so long recordings finish quickly.
Never uploaded
Your MKV file is converted inside your browser and never leaves your device.
Free, no watermark
No signup, no install, and nothing added to your file.
How it works
Choose a MKV file
Drop a MKV video up to 1 GB onto the converter, or pick it from your device.
Keep MP4 selected
MP4 is already selected. You can switch to another output format if you need one.
Convert and download
The video is converted in your browser. Preview the MP4 file, then download it.
What is a MKV to MP4 converter?
Keep the recording, lose the playback headaches.
MKV (Matroska) is a flexible container that can hold almost any video and audio codec. Streamers and screen recorders often record to MKV because a crash or power cut does not corrupt the whole file, unlike an unfinished MP4. The downside is that many editors, phones, and upload forms do not accept MKV.
When the MKV holds H.264 video and AAC audio, as most OBS recordings do, the converter moves the streams into MP4 without re-encoding. VP9 or AV1 video is re-encoded to H.264 so the MP4 plays everywhere.
When to reach for it
OBS and streaming recordings
Prepare a recorded stream or tutorial for editing and upload.
Editors that reject MKV
Import footage into Premiere, Final Cut, iMovie, or Jupitrr.
Playing on phones and TVs
MP4 plays on iPhones, Android, and most smart TVs.
Uploading to social platforms
Post clips where MKV uploads fail or are not supported.
Frequently asked questions
Can I convert MKV to MP4 in Safari?
Safari cannot open MKV files, so use Chrome or Edge on Mac or Windows. They read MKV files with H.264 or VP9 video.
Is converting MKV to MP4 lossless?
When the MKV holds H.264 video, yes: the streams are copied into MP4 untouched. VP9 and AV1 video is re-encoded to H.264, which changes the picture slightly.
Why is my converted MKV silent?
MKV files from movies or Blu-ray rips often use DTS or AC-3 surround audio, which browsers cannot decode. The video still converts, but the audio track may be left out. OBS recordings use AAC audio and are not affected.
What happens to subtitles and extra audio tracks?
The converter keeps the main video track and the first audio track. Subtitle tracks and additional audio languages are not carried into the MP4.
Is my MKV file uploaded to a server?
No. The MKV file is read and converted by your browser on your device. It is never sent to Jupitrr, and closing or refreshing the tab clears the working files.
Is there a file size limit?
Files up to 1 GB can be converted. Larger files can run out of browser memory, so trim or compress very long recordings first.
Unlock the full video workflow with Jupitrr AI
Jupitrr brings planning, scripting, recording, editing, and publishing into a single tool. Built for coaches and consultants shipping video consistently.
AI Talking Head Video Editor
Automatically add B-roll & Subtitles
- Unlimited Getty Images Stock Assets
- Unlimited Google Images & GIFs
- AI Generated Subtitles & Text Overlay
- Support 54+ Languages
Personalised AI Scriptwriter
Writes scripts in your tone
Trained on your scripts & viral scripting framework
Teleprompter App
Record without bad takes
Auto Jump-Cut & Silence Removal
Social Media Publishing
Post to all your channels
YouTube, Instagram, LinkedIn, TikTok, all at once.
Viral Video Search
Find what's trending
Get inspired for your next videos
