CloudConverterConvert MKV to MP4 when a video will not play on your TV, phone or editor. MKV can hold many tracks and is popular for downloads and recordings, but support for it is patchy.
MKV vs MP4: what changes
MKV (Matroska) is a flexible container that can hold several audio tracks, subtitles and chapters. MP4 is simpler and plays almost everywhere, including iPhones, smart TVs and video editors. Converting makes the file widely compatible, but extras such as multiple audio tracks and extra subtitles are not kept.
When to convert MKV to MP4
Use it for screen recordings from OBS and similar tools, downloaded videos, and any file that a TV, phone or editor will not open.
Before you convert
Only the main video and audio are converted, so extra audio tracks and subtitle tracks are not preserved. Output is limited to 1920 pixels on the longest side, so 4K videos become 1080p. The upload limit is 200 MB.
Tips for converting MKV to MP4
If your MKV is larger than 200 MB, cut a shorter section first or reduce the quality in your recording tool. Keep the original MKV in case you need the extra audio or subtitle tracks later.
Convert MKV to MP4 on any device
On Windows and Mac, drag the .mkv file onto the upload box, convert it and download the MP4. On a phone, you can pick the MKV from the Files app. Large MKV files are often bigger than the 200 MB limit, so check the file size first.
Frequently asked questions
Does the MP4 keep subtitles?
No. Only the main video and audio are converted. Subtitle tracks and extra audio tracks are not included.
Why is my MKV too big to convert?
Uploads are limited to 200 MB per file. For larger files, use a desktop tool or cut the video into shorter parts first.
Is the picture quality reduced?
The video is re-encoded to MP4. For normal viewing the difference is usually small, but a very high bitrate MKV may look slightly softer.
Can I convert 4K MKV?
Yes, but the output is scaled down to a maximum of 1920 pixels on the longest side.
Does it work on a phone?
Yes, if the file is within the 200 MB limit. Open this page in your phone browser and pick the file.
Is it free to convert MKV to MP4?
Yes. It is free, with no sign-up and no watermark.
Are my files kept after conversion?
No. Uploaded files are processed and deleted after your download. We do not keep a library of your files.
Is there a file size limit?
Uploads are capped at 200 MB per file.