Does converting MKV to MP4 lose quality?

Not when the tracks are copied. H.264, HEVC, and AAC move into MP4 unchanged; only tracks MP4 or browsers can't play are re-encoded.

My MKV has several audio tracks. Are they kept?

Yes. MP4 can hold more than one audio track, so each language is copied. Subtitle tracks are left out.

MKV to MP4

Convert an MKV video to MP4 that plays on phones, TVs, and editors. Processing stays on your device.

Files stay on your device

Drop a file to convert

See its format, then choose an output.

Any media file this browser’s engine can read.

How to convert MKV to MP4 online

Open a Matroska MKV file and export an MP4. Most MKV files hold H.264 or HEVC video with AAC audio, which the MKV to MP4 converter copies into MP4 without re-encoding, so large files finish quickly and keep their quality.

Step 1
Choose your MKV
Pick a file or drop it into the converter above.
Step 2
Keep MP4
MP4 is selected; choose another format if you need one.
Step 3
Download the MP4
Save the MP4 when the conversion finishes.

What to expect

Supported inputs: MKV videos and other readable video files.
What happens: Tracks MP4 can hold are copied unchanged. Dolby Digital audio is re-encoded so browsers can play the MP4, and other incompatible tracks are re-encoded or left out.
Limits: Subtitle tracks are not carried into the MP4. Tracks that need re-encoding depend on this browser's encoders and take longer.

Private by design

Your video stays on your device

Mastershot processes your file locally in this browser. It does not need to be uploaded to a server, and you do not need an account to use the tool.

No upload
No signup
No watermark