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Aug 25, 2026
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MKVToolNix for Mac is the free open-source toolkit for rebuilding MKV files on macOS, merging, splitting, retagging and extracting tracks without re-encoding anything, in a universal build native to both Apple Silicon and Intel.
A disc rip arrives with everything the disc had on it - six audio tracks, a dozen subtitle streams, chapters in the wrong places.
MKVToolNix is the second pass that turns it into the file you actually wanted.
Nothing gets re-encoded, so a two-hour film takes about as long as copying it.
Before You Download
CHECK YOUR MACOS VERSION
Current builds need macOS 13 Ventura or newer. Big Sur and Monterey are no longer supported, and the installer will not run on them. If you are on an older macOS, version 54 was the last release that supported Catalina.
The other thing worth knowing is that three separate disk images are published, and most people do not need the biggest one.
| Disk image | Size | Take this one when |
|---|---|---|
| arm64 | 28 MB | Your Mac has an M-series chip and you only need it for this machine |
| x86_64 | 31 MB | Your Mac is Intel |
| universal | 47 MB | You want one file that runs on both, or you are deploying across a mixed fleet |
All three run natively with no translation layer involved. The universal image simply carries both builds inside it, which is where the extra weight comes from.
One piece of context worth having: since version 98 the Mac disk images have been built by a community contributor rather than the project maintainer, who does not own a Mac. The Mac and Windows releases now ship within about a day of each other.
Why Nothing Loses Quality
A video file has two parts - the compressed streams, and the container holding them. MKVToolNix only ever touches the second one.
Tools like HandBrake and Shutter Encoder decode your video and compress it again, which costs time and a little quality every pass.
This copies the streams across untouched and writes a new wrapper around them. The guide on what remuxing actually means covers the distinction if the terms keep sliding around.
What You Can Do With It
| Task | What it solves |
|---|---|
| Merge | Combine video from one source with better audio from another, or fold external subtitle files into the video they belong to |
| Remove tracks | Delete the five commentary tracks and eleven subtitle languages a disc rip brought along |
| Set defaults and flags | Tag each track with its language and mark which plays first, so your player stops choosing wrong |
| Split | Break a long recording by size, duration or chapter |
| Edit chapters and metadata | Add proper chapter markers and track names that media libraries then display |
| Extract | Pull any single video, audio or subtitle stream back out as its own file |
The default-track flag is the one people find late. If a film keeps starting in the wrong language, or forced subtitles never appear, that is where it is fixed.
What Is in the Package
One graphical application and four command-line tools underneath it. Most people only ever open the first.
- MKVToolNix GUI is the interface, and it covers everything in the table above.
- mkvmerge is the multiplexer that does the actual work, and what you script against for batch jobs.
- mkvinfo reports a file's internal structure in Matroska-specific detail.
- mkvextract pulls individual tracks back out.
- mkvpropedit changes properties in place, without rebuilding the file at all.
That last one is worth knowing about. Renaming a track or changing a default flag with mkvpropedit rewrites a few bytes rather than the whole file, so it finishes instantly even on a 40 GB remux.
Formats It Reads
Input is not limited to MKV. It also reads MP4, AVI, MOV, MPEG, WebM, FLV, OGG and FLAC, which is what makes it useful for pulling scattered sources into one file.
Video covers H.264, HEVC, VP8, VP9, AV1, MPEG-1/2/4 and the legacy DivX and Xvid material. Audio runs to AAC, AC3, DTS, FLAC, MP3, Vorbis, Opus, TrueHD and PCM, and subtitles to SRT, ASS/SSA, VobSub, PGS and WebVTT.
Worth knowing. Remuxing does not make a file playable. If a codec was unsupported before, it stays unsupported after, because nothing about the stream has changed.
Installing It
Two routes, and the Homebrew one has a trap in it.
- The disk image. Mount the DMG, drag MKVToolNix to Applications, then right-click and choose Open on first launch to get past Gatekeeper.
- Homebrew. Use brew install --cask mkvtoolnix-app for the full application - the plain mkvtoolnix formula builds command-line tools only, with no interface.
MacPorts carries it too, covering all macOS versions and architectures, if that is already how you manage software.
Where It Sits in a Mac Workflow
Ripping comes first. MakeMKV for Mac gets the disc onto your drive intact, and the guide on how to use MakeMKV for free covers the beta key it expects.
If MakeMKV itself is the problem rather than the disc, the piece on MakeMKV's site going down explains what the error actually means.
MKVToolNix is the pass after that. Compression, if you need it, comes last through HandBrake.
For a quick trim with no track list involved, LosslessCut is faster to reach for. To check what is actually inside a file first, MediaInfo reports every codec parameter and bitrate.
If the container you are rebuilding is MP4 rather than MKV, MP4Box is the equivalent tool on that side.
Playing the Result
VLC for Mac opens MKV natively with Apple Silicon builds and needs nothing added.
Elmedia Player is the alternative if you want AirPlay and Chromecast, and IINA is the one to look at if a native macOS interface matters more than features.
For professional work, Pro Video Formats adds the ProRes and broadcast codecs that Final Cut Pro expects.
If you want an editor rather than a container tool, Shotcut for Mac and CapCut for Mac both give you a timeline.
Quick questions
Which macOS versions does it run on?
macOS 13 Ventura and newer. Monterey and Big Sur are not supported by current builds - version 54 was the last one that ran on Catalina.
Does it run on Apple Silicon?
Yes, natively, with no translation layer. There is an arm64-only disk image at 28 MB if you do not need the universal build's Intel half.
Why does macOS block it on first launch?
Gatekeeper stops unrecognised apps by default. Right-click the application and choose Open rather than double-clicking it, and the block only appears once.
Does splitting or merging reduce quality?
No. The streams are copied bit for bit and only the container is rebuilt, so the output matches the input exactly.
Can it convert MKV to MP4?
Not directly - it only writes Matroska files. MP4Box does the same lossless job on the MP4 side.
Is the Homebrew version the same thing?
Only the cask. brew install --cask mkvtoolnix-app gets the full application, while the plain formula builds command-line tools with no interface.
Windows users want MKVToolNix for Windows instead, and the rest of the catalogue sits under Mac downloads.
Download MKVToolNix 101.0 for Mac and see how it handles your files, or tell us how you got on if you have used it before.
