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MKV to MP4 Converter

MKV is a container format that many devices can't play directly. Convert to MP4 for broad compatibility with TVs, phones, and video editors.

🔒 No upload ⚡ Instant ✓ Free ∞ No size limit

Drop your MKV file here

or click to browse — converts instantly to MP4

No upload · Instant · 100% private

Why convert MKV to MP4?

MKV (Matroska) is a flexible open-source video container that can hold almost anything: multiple video streams, multiple audio tracks, subtitles, chapters, metadata. It's popular for movies, TV episodes, and anime because it can pack all those features into a single file. The downside is that many devices, especially older smart TVs, phones, and game consoles, don't play MKV files at all.

MP4 is the universal video container. It can do most of what MKV does — multiple audio tracks, subtitles, chapters — but unlike MKV, it's supported by virtually every device, browser, and media player made in the last 15 years.

If you've downloaded an MKV that won't play on your phone, smart TV, or in a web browser, converting to MP4 makes it work everywhere with no visible quality difference.

About MKV

MKV (Matroska Video) is an open-source multimedia container released in 2002. Its key feature is flexibility — it can hold multiple video, audio, and subtitle streams in a single file. Because it's so capable, it's the format of choice for high-quality movie and TV releases. Compatibility outside dedicated media players is limited.

About MP4

MP4 (MPEG-4 Part 14) is the universal video format. It supports the same modern codecs as MKV (H.264, H.265) and can also hold multiple audio tracks and subtitles, but with much broader device support.

Quality and file size

When the MKV uses standard codecs (H.264 or H.265), the conversion to MP4 is essentially a remux — the video and audio data are repackaged into the new container with no re-encoding and no quality loss. If the MKV uses uncommon codecs that don't fit in MP4, Filesmith re-encodes them, which introduces a small quality loss.

Filesmith runs entirely in your browser using WebAssembly. Files are never uploaded to any server — conversion happens locally on your device, instantly and privately.

Accepts: MP4, WEBM, MOV, MKV, AVI, FLV

Frequently asked

Will I lose quality converting MKV to MP4?

Usually no. If your MKV uses standard H.264 or H.265 video and AAC audio, the conversion is just a container swap with no quality change.

Why won't my MKV play on my smart TV?

Most smart TVs and phones are built around MP4 and don't include MKV support. MP4 is the safer cross-device choice.

Will subtitles and multiple audio tracks be preserved?

MP4 supports both, though some media players handle them differently. For most files everything carries over.