Convert MKV to MP4

MKV → MP4. Source file ≤ 2 GB · Output ≤ 1 GB.

Matroska can hold several kinds of video and audio codecs. MP4 is a video container, not a codec. Its actual video and audio codecs depend on the file.

MKV → MP4: Example settings

60 s • H.264 4,000 kbps + AAC 192 kbps ≈ 31.44 MB

MP4: Output

Sizes are examples, not guarantees. Container overhead is extra; variable bitrate and image content change the result. Keep the original and compare the output.

Remux or re-encode?

MKV and MP4 are containers. Remuxing copies compatible compressed streams into a different container without re-encoding; it can preserve quality and be faster. This web tool re-encodes video instead of offering a stream-copy/remux mode. If your player already plays the MKV and you need no other changes, conversion may be unnecessary. Renaming .mkv to .mp4 does not convert the file.

Make a playback copy

For a broadly compatible copy, select MP4 with H.264 video and AAC audio. Test a short file on the intended phone, player or editor before converting a long recording. Re-encoding can change picture quality and file size; matching the source bitrate does not guarantee identical quality. This is not an archive of every MKV track, attachment or subtitle. Keep the original.

When the result is too large or fails

The web video output limit is 1 GB, even when an input up to 2 GB is accepted. A larger input allowance is not a promise that every output fits. Reduce bitrate or dimensions where appropriate, or use the desktop workflow. Check picture, sound, duration and playback after download. Unusual codecs and multi-track sources can require a different local workflow.

A checked example where MP4 was larger

Our generated 1-second 160 × 90 MKV with H.264 video and an AAC tone was 26,023 bytes. With the web MP4/H.264/AAC conversion settings, the result was 100,695 bytes and decoded successfully at 1 second. This small test shows why changing the container is not a size-reduction promise: the web tool re-encodes. It is not a quality benchmark or a prediction for your recording.

JavaScript is required for file selection and processing.