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Convert MKV to MP4
Turn an OBS recording or downloaded MKV into an MP4 your phone and editor can open. Your file is never uploaded — it's processed right here in your browser.
How it works
01. Add your MKV file
Drop or choose your MKV file. Other video formats work too.
02. Leave the rest to us
Nothing to choose. H.264 video is copied; only audio that doesn't suit MP4 becomes AAC.
03. Download the MP4
Hit Convert and download your MP4 file when it's ready.
Why convert to MP4?
MKV survives crashed recordings, so OBS loves it — but iPhone, Premiere and Instagram often won't take it.
How the conversion works
H.264 or HEVC video is copied without re-encoding. Audio that MP4 players struggle with, like Opus, is converted to AAC, so even long recordings finish quickly.
Frequently asked questions
My OBS recording has several audio tracks.
The primary video and audio tracks go into the MP4. If you recorded mic and game audio separately, check which one is the default track in OBS.
Is my video stored anywhere?
No. The file never leaves your device — it's processed inside this tab with WebCodecs. Close the tab and nothing is left behind.
Is there a file size limit?
Up to 2 GB per file. The result is held in your browser's memory, so on devices with little RAM smaller files are safer.
Which browsers are supported?
Recent Chrome, Edge, Safari and Firefox. Speed depends on your device — desktop Chrome and Edge are usually the fastest.
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- Video Converter — Convert between MP4, WebM, MOV and MKV for free, no install. When the codec fits, it's instant and lossless.
- Video Trimmer — Cut out just the part you want. Drag the start and end, or type exact times.
- MP4 → MP3 — Convert MP4 to MP3 for free. Pull the audio out right in your browser.
Got a long video? Make it many shorts
Shorts Zone finds the best moments in a long video and turns them into captioned vertical shorts in one go. Just like this tool, your video never leaves your device.