Convert MKV to MP4, Free
Upload your MKV file and get a MP4 in seconds. No account, no watermark.
How to convert MKV to MP4
MKV (Matroska Video) is a flexible open-standard container that can hold multiple video streams, audio tracks, and subtitle tracks in a single file. It is popular for media archiving and high-quality video downloads. The problem is that MKV has limited support on smart TVs, mobile devices, and streaming platforms, many of which require MP4.
Converting MKV to MP4 typically involves re-wrapping the video and audio streams from the Matroska container into an MP4 container. When the video codec is already H.264 (which is common), re-encoding is not required and conversion is fast. BoltConverter handles both re-wrapping and re-encoding depending on what the source file contains.
Upload your MKV file
Click the upload area or drag your .mkv file onto the page. Files up to 500 MB are supported.
Streams are moved to an MP4 container
BoltConverter re-wraps the video and audio streams from the MKV into an MP4 container on our servers. Re-encoding only occurs if required by the codec.
Download the MP4
Click Download to save the MP4 file. It will play on any device, smart TV, or media player.
Files are deleted automatically
Both the original MKV and the converted MP4 are removed from the server after your download.
Frequently asked questions
Will my subtitles be preserved when converting MKV to MP4?
Subtitle tracks embedded in the MKV are not always carried over to the MP4 container because MP4 has more limited subtitle format support. Text-based subtitle tracks may be dropped. For subtitles, consider burning them into the video before converting.
Will there be quality loss?
If the video is already H.264, BoltConverter re-wraps without re-encoding and there is no quality loss. If re-encoding is required, a high-quality preset is used to minimize any visible degradation.
Can I keep multiple audio tracks?
The primary audio track is preserved. Multiple alternate audio tracks from the MKV may be dropped, as MP4 has different handling for multi-track audio.
Is there a file size limit?
MKV files up to 500 MB are supported. For larger files, consider splitting the video first.
Are my files stored after conversion?
No. Both the uploaded MKV and the converted MP4 are deleted from our servers as soon as you download the result.