MKVToolNix for PC: How to Download and Install on Windows (2026 Guide)

Your movie plays with the wrong subtitle track, an unwanted dubbed audio track starts first, or a subtitle file sits next to the video instead of inside it. Fixing any of this in a normal editor means a long, quality-damaging re-encode — for what should be a ten-second job.

This guide shows you how to download MKVToolNix for PC from its official website, install it on Windows 11 or 10, and add or remove subtitle and audio tracks in an MKV file. Key features, system requirements and cost answers are all covered below.

What Is MKVToolNix?

MKVToolNix is a free, open-source set of tools for working with Matroska (.mkv) video files, developed mainly by Moritz Bunkus. Its main window — the multiplexer in mkvtoolnix-gui — lets you open a video file, see every track inside it (video, each audio track, each subtitle track, chapters and attachments), and then add, remove, reorder or relabel those tracks before saving a new MKV.

The crucial point is what MKVToolNix does not do: it never re-encodes. It copies the existing audio and video data into a new container — multiplexing, or remuxing — so quality is identical to the original and the job finishes in seconds or minutes instead of hours. The package also includes a header editor, a chapter editor and an info tool for inspecting any MKV.

Key Features of MKVToolNix

Track control: Add, remove, reorder and rename audio, subtitle and video tracks inside MKV files.
No re-encoding: Remuxing copies the original streams, so quality is untouched and jobs finish fast.
Default and forced flags: Choose which subtitle or audio track players select automatically.
Header editor: Change a file’s title, track names and flags in place, without remuxing the whole file.
Chapter editor: Create, edit and save chapter markers for long videos and rips.
Attachments support: Embed or extract cover images and the fonts some subtitle styles need.
Job queue and presets: Line up several remux jobs and save your favourite track settings for next time.

System Requirements

Operating System: Windows 11 or Windows 10 (64-bit)
Processor: Any modern Intel or AMD CPU — remuxing is limited by disk speed, not CPU
RAM: 2 GB is plenty
Storage: Around 100 MB for the program, plus free space equal to the files you produce
Internet: Only needed for the initial download
Account: None — no sign-up or licence of any kind
Files: Input can be MKV, MP4, AVI and more; output is always MKV

How to Download MKVToolNix (Official Method)

Utility collections like MKVToolNix get mirrored on download portals that wrap them in their own installers. The project maintains one official home — the website linked below — where the genuine Windows installer and a portable version are published free.

Official Website: Download MKVToolNix from the official website

Step-by-Step Installation

Open the official MKVToolNix downloads page linked above and find the Windows section.
Download the 64-bit installer (named like mkvtoolnix-64-bit-x.x.x-setup.exe); a portable build is listed alongside it.
Save the file to your Downloads folder and double-click it to start setup.
Approve the Windows permission prompt and choose your language.
Accept the licence agreement and keep the default installation folder.
Click Install, then close the setup wizard when it finishes.
Launch “MKVToolNix GUI” from the Start menu — the multiplexer opens by default.

First-launch note: The GUI opens on the multiplexer, where almost everyone spends their time. The other tools — header editor, chapter editor, info, job queue — live in the menu on the left; ignore them until a job needs one.

How to Add or Remove Subtitle and Audio Tracks in MKVToolNix

Open MKVToolNix GUI and drag your video file into the “Source files” box (or click “Add source files”).
Look at the middle list: every track inside the file appears, with its type, language and codec.
Untick any track you want to remove — an unwanted dubbed audio track or duplicate subtitles, for example.
To add a subtitle, drag the external .srt file into the source files box too; it appears in the track list, ticked.
Select your new subtitle track and set its language, and tick “Default track” if players should show it automatically.
Choose the output filename at the bottom, then click “Start multiplexing” — a new MKV is written in seconds, original untouched.

Is MKVToolNix Really Free?

Yes — entirely. MKVToolNix is free and open-source software under the GPL, and the official download is the complete toolset: multiplexer, header editor, chapter editor, info tool and job queue, with no premium version, no ads and no feature limits. The developer accepts voluntary donations, but paying is never required. Any website charging for MKVToolNix is selling something that is free at the source.

Frequently Asked Questions

Is MKVToolNix safe to download and use?
Yes, from the official website linked above. MKVToolNix is a long-running open-source project with public code, trusted throughout the video community. It only writes new files and never alters your originals unless you deliberately edit headers in place. Avoid third-party portals.

Will remuxing reduce my video quality?
No. Multiplexing copies the existing audio and video streams bit-for-bit into a fresh MKV container; nothing is decoded or re-encoded, so picture and sound are identical to the source. That is also why it is so fast compared with a video editor.

Can MKVToolNix convert MP4 or AVI files?
It can take MP4, AVI and many other formats as input and produce an MKV containing the same streams — a container change, not a conversion. It cannot turn an MKV into an MP4, change codecs, or shrink a file; for real conversion you need an encoder such as HandBrake.

Why does my new subtitle track not show automatically in my player?
Players choose subtitle tracks using the flags MKVToolNix sets. Select the track before multiplexing and mark it “Default track”; also set its language correctly, because some players auto-select by language. If it still does not appear, check your player’s own subtitle settings.

Conclusion

MKVToolNix is the quiet specialist every video collector ends up needing: total control over the tracks inside an MKV, with zero quality loss and zero cost. Download it from the official website, open that misbehaving file, and fix its tracks in less time than the opening credits.

Download MKVToolNix from the Official Website

MKVToolNix for PC: How to Download and Install on Windows (2026 Guide)