How to use the MKV to MP4 converter
- Choose your MKV video or drop it on the box.
- Check the settings. "Same as original" resolution is fastest and lets fast mode copy compatible videos without re-encoding. Lower it to 720p for a smaller file.
- Click "Convert to MP4". A progress meter shows how far along it is.
- Download your MP4.
Why convert MKV to MP4?
MKV does not play on iPhone, iPad, in iMovie or on many websites. Most MKV files contain H.264 video, which can be moved into MP4 without re-encoding.
- MKV: not supported by Apple devices or many editors.
- MP4: plays almost everywhere.
- MP4: good quality at small sizes with H.264.
For H.264 MKV files, fast mode copies the video and audio as they are, so a full film converts in seconds. HEVC MKVs are re-encoded to H.264 unless you untick "Play everywhere". Subtitle tracks are not kept in MP4; extract them first if you need them.
MKV vs MP4
| MKV | MP4 | |
|---|---|---|
| Full name | Matroska Video | MPEG-4 Part 14 |
| Type | Video | Video |
| Created by | the Matroska open-source project (2002) | Moving Picture Experts Group (MPEG) (2001) |
| Compression | Lossy | Lossy |
| Typical codecs | H.264, HEVC or VP9 + AAC, AC3, DTS or Opus | H.264 + AAC |
| Best for | Movies with several languages or subtitles, OBS recordings and archiving | Sharing videos online, phone recordings, social media uploads and streaming |
| Plays on | VLC, MPV, Kodi, Plex and most smart TVs; iPhone, iPad, QuickTime and many video editors do not open MKV | Windows, macOS, iPhone, Android, smart TVs, game consoles and every modern browser |
Does converting MKV to MP4 lose quality?
Often none. When the MKV contains H.264 video, MP4 can hold it as it is, so fast mode copies the streams without re-encoding. Other codecs (including HEVC while "Play everywhere" is ticked) are re-encoded at "Balanced" quality, which looks the same as the original to most people.
How long does it take?
Seconds when fast mode applies, even for a full film. If the video must be re-encoded, expect a few minutes for a long HD video.
What is an MKV file?
MKV (Matroska) is a free, open container that can hold almost any video, audio and subtitle format in one file, including many audio languages and subtitle tracks. That flexibility makes it popular for movie and series files and for screen recorders like OBS.
What is an MP4 file?
MP4 is a container that usually holds H.264 or H.265 video with AAC sound. It is built on Apple's QuickTime file structure and became an ISO standard in 2001. Because almost every phone, browser, TV and editing app can play it, MP4 is the safest choice when you need a video to just work.
Frequently asked questions
Do I have to pay or sign up to use the MKV to MP4 converter?
No. There is no account, no payment and no watermark. The only limit is 1 GB per file, set by what browsers can handle.
Are my files safe?
Yes. Files are converted locally in your browser and are never uploaded. When you close the page, nothing is left behind.
Will the MP4 sound and look as good as the MKV?
Often none. When the MKV contains H.264 video, MP4 can hold it as it is, so fast mode copies the streams without re-encoding.
Can I convert MP4 back to MKV?
Yes, use the MP4 to MKV converter.
An MKV will not play on iPhone or in iMovie. What should I do?
Convert it to MP4. If the video is H.264 or HEVC, the conversion is a fast copy with no quality loss.
Does it work on iPhone and Android?
Yes, in Safari, Chrome and other modern mobile browsers. Short files work best on phones; for long or high-resolution videos a computer is faster.