Online Tool Store
MKV to MP4 Converter
Remux an MKV file into an MP4 container without re-encoding, keeping the original quality. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
How it works
- Choose an .mkv file.
- Click "Convert to MP4" — the streams are repackaged into an MP4 container.
- Preview or download the result.
FAQ
Does this re-encode my video?
No — it repackages (remuxes) the existing video and audio streams into an MP4 container without re-encoding, so it's fast and there's no quality loss.
Why did my conversion fail?
MP4 can only hold certain codecs. If your MKV uses a codec MP4 doesn't support (e.g. VP9 video or Vorbis audio), the remux will fail — that's a container limitation, not a bug. Re-encoding to a supported codec would need a different, slower tool.
Is my video uploaded anywhere?
No — conversion runs entirely in your browser using a WebAssembly build of FFmpeg. The file never leaves your device.
Is there a file size limit?
No hard limit, but very large files are bounded by your browser's available memory.
How we compare
| Feature | Online Tool Store | Desktop video converters | Other online converters |
|---|---|---|---|
| No file upload — runs in your browser | ✓ | ✓ | ✗ |
| No install | ✓ | ✗ | ✓ |
| Lossless (no re-encoding) | ✓ | ✓ | ✗ |
Many online converters re-upload your file to a server and re-encode it, losing quality and taking longer. MKV to MP4 Converter repackages the streams as-is, on your device.