Mkvtoolnix how to Split MKV File
Split MKV files directly in MKVToolNix by using the "Split" feature in the GUI or command-line, which lets you divide a video into segments by size, duration, or timestamp without re-encoding.
How to Split MKV Files in MKVToolNix
MKVToolNix 91.0.0 handles MKV splitting through its graphical interface with zero quality loss. The process differs depending on whether you want to divide by file size, duration, or specific timestamps. Unlike lossy converters, this tool remuxes your video, meaning the original H.264, H.265, or HEVC streams stay intact—only the container changes.
Open the MKVToolNix GUI and load your source MKV file. Navigate to File → Open (or drag the file directly into the window). Once loaded, click the "Split" tab at the top of the interface. You'll see three split modes: by size, by duration, and by timestamp.
Splitting by File Size
Choose this mode if you need output files under a specific limit—useful for uploading or storing on devices with capacity constraints. Select "Split by size" from the dropdown menu, then enter your desired file size in megabytes. The tool calculates how many segments you'll get and displays them in the preview window below.
For example, entering 500 MB will divide a 2 GB MKV into approximately four files. The software intelligently places split points at keyframes to avoid corruption.
Splitting by Duration
Select "Split by duration" to create segments of equal length. Enter the time span (hours:minutes:seconds format) and the tool generates segments accordingly. A two-hour film split by 30-minute intervals produces four files. This method works reliably for batch processing multiple videos—mkvtoolnix how to split mkv file using duration handles frame-accurate positioning across all tracks simultaneously.
Splitting by Timestamp
The timestamp method provides manual control. Click "Split by timestamp" and specify exact points where you want cuts. Press the "+" button to add each split point. This approach suits chapter-based division or removing unwanted sections while keeping everything else intact.
Configuring Output and Tracks
Before finalizing, configure which audio tracks, subtitle streams, and video data to include in each segment. The track selection panel below the split settings lets you deselect unwanted audio languages or subtitle formats (SRT, ASS, etc.). Leave all checked if you want complete copies of everything.
Set your output directory in the "Output" field. MKVToolNix automatically names segments sequentially (e.g., output-001.mkv, output-002.mkv). Change the base filename if needed.
Running the Split Operation
Click "Start multiplexing" to begin. Progress displays in real-time. Depending on file size and your system, this takes anywhere from seconds to minutes. Since remuxing doesn't re-encode, it's significantly faster than video editing software.
When to Use Split vs. Merge
If you later need to recombine segments, the MKVToolNix GUI includes a merge function for stitching files back together. Conversely, extracting subtitles or editing metadata doesn't require splitting—those tools work on the complete file.
MKVToolNix operates as a free MKV editor without watermarks or file limits. For audio-only splitting, consider Fre:ac as a specialized audio converter instead.
Final Notes on mkvtoolnix how to split mkv file
All output remains lossless regardless of your splitting method. The process preserves original video quality, audio fidelity, and subtitle synchronization. Mkvtoolnix how to split mkv file works on Windows 10, Windows 11, and Linux systems—both 64-bit and 32-bit architectures. The software is open-source, safe to download, and requires no registration or paid upgrades to access splitting functionality.