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Converter Tools

MKV to MP4 Converter

Play MKV videos on devices and apps that only accept MP4. Most MKV files contain H.264 or HEVC video that can be moved into MP4 instantly without any loss of quality; others are converted to H.264 automatically.

  • Files stay on your device
  • No sign-up
  • Free to use

How to use MKV to MP4

  1. Drop an MKV file onto the upload area.
  2. Keep Fast to remux the video without re-encoding, or choose Compatible to convert everything to H.264 and AAC.
  3. For Compatible, choose the quality and optional maximum resolution.
  4. Select Convert to MP4 and download.

MKV to MP4 features

Lossless remux

Copies the video stream into MP4 without re-encoding, usually in seconds even for long files.

Audio made compatible

Converts audio such as AC-3, DTS, FLAC or Opus to AAC, which MP4 players expect.

Automatic fallback

If the video codec cannot go into MP4, it is converted to H.264 instead.

Main tracks selected

The first video and audio tracks are kept, which suits most single-language files.

Compatibility mode

Full H.264 conversion for older TVs, game consoles and phones.

Runs in your browser

Files are not uploaded.

When to use MKV to MP4

  • Playing MKV recordings from OBS on phones and tablets.
  • Importing MKV footage into editors that do not accept Matroska.
  • Uploading recordings to platforms that require MP4.
  • Playing MKV files on smart TVs and consoles that only support MP4.
  • Converting anime and film rips for portable players.

MKV to MP4 FAQ

Will I lose quality converting MKV to MP4?

Not in Fast mode: the video is copied bit for bit. Audio is converted to AAC at a high bitrate. Compatible mode re-encodes video, with a small, usually invisible quality loss.

What happens to subtitles and extra audio tracks?

The first video and first audio track are kept. MKV files often carry several languages and subtitle formats that MP4 cannot store; extract subtitles separately if you need them.

Why use MKV at all?

MKV (Matroska) is an open, very flexible container that can hold any codec, multiple audio and subtitle tracks, chapters and attachments. That makes it popular for recordings and archives, but less supported by consumer devices.

My OBS recordings are MKV. Why?

OBS recommends MKV because a crash or power cut does not corrupt the whole file, unlike MP4. Remuxing to MP4 afterwards, as here, is the standard workflow.

Is there a size limit?

Up to 500 MB per file. Fast mode handles large files easily since nothing is re-encoded.

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Matroska and MP4: two containers, one video

Matroska, the format behind .mkv files, was created in 2002 as an open, extensible container. Its structure is designed to survive damage and to hold practically anything: several video and audio tracks, many subtitle formats, chapter markers and even fonts. That robustness is why screen recorders like OBS default to it.

MP4 is more restrictive but far more widely supported in hardware. Phones, televisions, cars and browsers all play H.264 in MP4. The good news is that the video inside most MKV files is already H.264 or HEVC, both of which MP4 can carry. Moving the stream from one container to the other, called remuxing, is fast and lossless.

Audio is the usual compatibility issue. MKV files often contain AC-3, DTS, FLAC or Opus audio that MP4 players may not decode. This tool converts the audio track to AAC while copying the video, which is the combination with the broadest support.

If a file uses a video codec that MP4 cannot store, or the remuxed file still does not play on an older device, the Compatible option re-encodes the video to H.264 for maximum compatibility.

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