Mkvtoolnix how to Use

Updated: June 4, 2026 · Full review · Alternatives · Converters

MKVToolNix lets you create, merge, and edit Matroska video containers without spending a cent. This open-source tool works on Windows and Linux, handling everything from combining multiple MKV files to extracting audio tracks and managing subtitles — all through a user-friendly GUI or command line.

Getting Started with MKVToolNix

The first step is grabbing version 91.0.0 from the official repository. The software runs as either a portable version or a standard installation on Windows 10, Windows 11, and Linux Ubuntu systems. Both 32-bit and 64-bit builds are available, so check your system specs before downloading. Learn where to safely download MKVToolNix to ensure you're getting the legitimate release.

Once installed, launch the GUI and you'll see a straightforward interface. The main window displays your project workspace where you'll add video files, audio tracks, subtitles, and metadata. No confusing menus hidden three levels deep — everything you need sits right in front of you.

Understanding mkvtoolnix how to use for Basic Tasks

The core workflow involves three main operations: adding files, configuring tracks, and outputting your final container.

Merging Video Files

This is where mkvtoolnix how to use shines. Click "Add Source Files" and select your first video. The software reads all tracks — video, audio, and subtitle streams. Then add your second file. You'll see both listed in the source panel. Configure which tracks from each file you want in the output (useful if you want audio from file A but subtitles from file B), set your output filename, and hit "Start multiplexing." The merge happens without re-encoding, keeping your H.264 or H.265 video quality intact.

Adding and Synchronizing Subtitles

Adding subtitles is equally straightforward. Import your SRT or ASS subtitle files through the "Add Source Files" menu. The MKV subtitle editor lets you set the subtitle language, delay synchronization if they're out of sync, and choose whether they're default or forced. You can embed multiple subtitle tracks in a single file — handy for multilingual content.

Extracting Tracks

Need to pull audio from an MKV? Right-click the file in your source list, select "Extract tracks," choose which audio or subtitle stream you want, and save it separately. The extraction preserves original quality since it's not transcoding.

Working with Container Formats

MKVToolNix handles Matroska files natively, but the WebM container editor functionality lets you work with WebM videos too. You can convert between MKV and WebM containers without losing data — it's pure remuxing, not conversion. The tool also recognizes MP4 and AVI sources, though output defaults to MKV (which is usually what you want anyway).

Advanced Features

Chapter editing deserves a mention. You can create, modify, or remove chapter markers directly in the tool. Batch processing via command line interface handles repetitive tasks — merge ten files overnight without touching the GUI. Track selection gives granular control: keep only specific audio languages, remove commentary tracks, or strip out subtitle streams you don't need.

Pro Tip: Use the "Preferences" panel to set default output directories and naming conventions. Create a template with your preferred language tags and track names — the software remembers these, cutting your setup time on future projects by half.

Comparing Your Options

If you need broader functionality beyond MKV editing, File Converter handles video, audio, and document conversions in one tool. For audio-only work, Fre:ac specializes in audio conversion with CD ripping support.

Final Take on mkvtoolnix how to use

This free MKV merge tool beats paid competitors on features alone. No ads, no nag screens, no limitations on file size or processing speed. Whether you're remuxing video files, embedding subtitles, or splitting chapters, the software delivers professional results without the professional price tag.