How to Convert MP4 to MKV on Windows/Mac/Online?

Table of Content

The Best Way to Convert MP4 to MKV

5 Common Ways to Convert MP4 to MKV

2 Ways to Convert MP4 to MKV Online

FAQs

Sum up

MP4 and MKV are both containers, not quality levels. Converting MP4 to MKV is useful when you want a more flexible container for multiple audio tracks, soft subtitles, chapters, or easier playback in some media servers and players. The video quality depends on whether you re-encode the video and what settings you choose.

For a single file, most converters can do the job. For many MP4 videos, a batch converter is more practical because you can add all files once, select MKV once, and let the program finish the queue. Below are desktop, free, command-line, and online methods for different needs.

Part 1. Best Way to Convert MP4 to MKV in Bulk

# WonderFox HD Video Converter Factory Pro

Platform: Windows

WonderFox HD Video Converter Factory Pro is a powerful yet beginner-friendly video converter for Windows. It supports 600+ output profiles and, more importantly for this topic, allows you to add a folder or many MP4 videos and batch convert them to MKV in one go. You can keep the original quality, change codecs, make HEVC MKV files, create HD/4K MKV videos, or compress the output according to your needs.

When the output settings are compatible with the source, the software may enable Lightning Mode to change the container from MP4 to MKV without re-encoding. This is much faster and avoids extra quality loss. If you change the codec, resolution, bitrate, or other parameters, the program will re-encode the video with your selected settings.

Now, download and install download and install the software on your PC. Follow the instructions to convert one or multiple MP4 videos to MKV in simple clicks:

Step 1. Open HD Video Converter Factory Pro > Converter.

Step 2. Click Add Files to select the MP4 file(s) you want to convert, or drag and drop them into the software directly. To batch convert MP4 to MKV, add all target files at this step.

Step 3. Go to “Click to change output format” on the upper right. Navigate to the Video tab and choose MKV as the output format. For 4K MKV output, open the 4K/UHD category and choose a suitable MKV profile.

Optional. Press “Parameter settings” to change the video codec, resolution, bitrate, frame rate, audio settings, volume, etc. Leave the settings as Smart Fit if you simply want a quick, balanced result.

Step 4. Choose an output folder and click Run to start conversion. The program will process the imported files automatically, so you do not need to repeat the same settings for every MP4 video.

Some users would like to convert MP4 to MKV with subtitles, and HD Video Converter Factory Pro can also achieve that. Here is a complete guide: How to Convert Video with Subtitles?

For large batches, keep an eye on the output folder and available disk space. If you keep original codecs, the converted MKV files are usually close to the source size. If you increase resolution, bitrate, or use a different codec, the file size and conversion time can change.

Beyond changing the video container format, HD Video Converter Factory Pro lets you compress file size, record and edit MP4 or MKV files, and more. It is full-featured yet still easy to use for everyone.

Part 2. Other Common Ways to Convert MP4 to MKV

# Free HD Video Converter Factory

Platform: Windows

Free HD Video Converter Factory is a handy free video converter for Windows that can convert MP4 files to MKV without complicated settings. There are 300+ export formats in this free software. You can convert MP4 not only to MKV but also to AVI, WMV, MOV, and even audio files.

It doesn’t matter whether it is your first time using the software because the process is quite easy and quick. DownloadDownload the free video converter and change MP4 to MKV with the following steps. For bigger batch jobs and more output settings, use the Pro method in Part 1.

Step 1. Launch Free HD Video Converter Factory and open the Converter.
Step 2. Click the Add Files button or drag and drop the source MP4 video into the program.
Step 3. Click the format image on the right side of the interface. Then, select MKV under the Video tab as the output format.
Step 4. Click to specify an output path and press Run to finalize the conversion process.

# VLC

Platform: Windows, Mac

VLC is mainly a media player, but it also includes a basic conversion feature. If you have installed the application, you can use it to convert videos between various formats, including MP4 to MKV. It is useful for occasional conversions, but it is not the most convenient choice for a large batch of files.

In addition, advanced users can customize the video/audio codec, resolution, subtitle, and other settings of the output profile. Since VLC conversion settings are not as clear as a dedicated converter, check the output file before deleting the original MP4.

Let’s see how to convert MP4 to MKV using VLC media player:

Step 1. Open VLC. Click Media on the top menu bar and select Convert / Save from the drop-down list. (Or use the hotkeys Ctrl + R.)
Step 2. Click the Add button to load the MP4 files you want to convert.
Step 3. Press Convert / Save at the bottom of the window.
Step 4. Go to the Profile in Settings. Click on the last icon to create a new profile like Video – H264 + MP3 (MKV):
under Encapsulation, select MKV;
under Video codec, check Video and change the Codec to H-264;
under Audio codec, check Audio and change the Codec to MP3.
Then, type Video – H264 + MP3 (MKV) in the Profile Name box and click Create. Select the new profile as the output format.
Step 5. Click the Browse button to specify an output file name and destination.
Step 6. Click Start to convert MP4 video to MKV with VLC.

# HandBrake

Platform: Windows, Mac

HandBrake is a well-known video transcoder program that works on Windows and Mac. It can open many common video files and save them as MKV, MP4/M4V, WebM, and, in newer versions, MOV. Note that HandBrake is designed for transcoding, so it will usually re-encode the video instead of only changing the container.

How to convert MP4 to MKV format with HandBrake? Follow the below steps:

Step 1. Run HandBrake on your PC or Mac. Then, select the File option to open an MP4 video file.
Step 2. Go to the Summary tab and select the Format as MKV.
Step 3. Change the video dimensions, apply filters, and specify a save path as needed. For multiple MP4 files, add them to the queue before starting.
Step 4. Press the Start Encode or Start Queue icon at the top toolbar and wait for the process.

# Format Factory

Platform: Windows

Format Factory is an ad-supported media converter for Windows. It can convert multiple media files, including videos, audio, pictures, DVDs, and CDs. It supports video conversions between MKV, MP4, WebM, AVI, and many other formats and allows you to edit videos by merging, clipping, cropping, etc.

Learn how to convert MP4 to MKV with Format Factory here:

Step 1. Open Format Factory. In the Video section, scroll down to select – > MKV.
Step 2. Click Add Files to import MP4 videos from your PC.
Step 3. Choose an export file path in the bottom left corner. You can also edit the video files and adjust output settings based on needs. Once done, press OK to save the changes.
Step 4. Click the Start button at the top of the main interface and wait until the conversion is complete.
Tips: If a “Format Factory error 0x00000001” or “Format Factory Not Recognized/Supported” error occurs when converting files, you can fix it by following the simple methods in this post >>

# FFmpeg

Platform: Windows, Mac

Another method to convert MP4 to MKV on Mac and Windows is FFmpeg. It is open-source and includes a suite of libraries to handle video, audio, and other multimedia files. FFmpeg supports virtually all video file types and converts them to another format using command-line.

How to convert MP4 to MKV on Mac or Windows with FFmpeg:

Step 1. Download FFmpeg and put ffmpeg.exe into the same folder as your target MP4 file.
Step 2. On Windows, open Command Prompt or type “cmd” in the address bar and press the Enter key.
On Mac, open Terminal, type “cd desktop”, and press the Return key.
Step 3. Then, enter the conversion command:
ffmpeg -i input.mp4 -vcodec copy -acodec copy output.mkv
(In this command line, replace “input” with the MP4 video filename and “output” with your desired name for the resulting MKV file. “vcodec copy” and “acodec copy” mean you will keep the video and audio codecs as the original. Advanced FFmpeg users can change them based on needs.)
Step 4. Press Enter/Return to run the command, and FFmpeg will convert MP4 into MKV immediately.
Step 5. Check the output MKV file in the same folder as the original MP4 video.

To batch remux all MP4 files in the same folder on Windows, you can use this command in a .bat file:
for %%a in (*.mp4) do ffmpeg -i "%%a" -c copy "%%~na.mkv"
For macOS Terminal, use:
for f in *.mp4; do ffmpeg -i "$f" -c copy "${f%.*}.mkv"; done

Part 3. How to Convert MP4 to MKV Online? (2 Ways)

# https://www.mkv.to/mp4-mkv/

Platform: online

MKV.to is a handy online tool that can convert an MP4 file to MKV in a browser. It is convenient when you do not want to install software, but online converters may limit file size, conversion times, upload speed, and download availability. Check the current limits on the website before uploading a large video.

Simple clicks to convert MP4 to MKV with the MKV.to tool:

Step 1. Visit the website and click Select your files to add an MP4 video from your computer.
Step 2. Click Convert files, and it will automatically convert your MP4 to MKV.
Step 3. Wait for the process. Once done, download the converted .mkv file to your device.
* The server-side storage time and privacy rules may change, so avoid uploading private or sensitive videos to online converters.

# https://www.aconvert.com/video/mp4-to-mkv/

Platform: online

If you want to convert more than one MP4 file to MKV in the browser, Aconvert is another option. It provides more conversion options than some simpler online tools, enabling you to alter the video size, bitrate, frame rate, aspect ratio, etc. However, it still depends on upload/download speed and current file size limits, so desktop software is usually better for large or private videos.

Step 1. Open the online tool and click Choose Files to load your MP4 video(s).
Step 2. The target format is MKV by default, and you can click Options to select Change Size, bitrate, or frame rate.
Step 3. Click the blue Convert Now! button to start converting.
Step 4. The conversion results will be displayed below. You can preview the output video and save it to your computer.

Frequently Asked Questions

Q1. Is MKV better than MP4?

Not always. MKV and MP4 are both containers. MKV is more flexible for multiple audio tracks, subtitles, chapters, and some advanced playback needs, while MP4 usually has wider compatibility with phones, TVs, browsers, and social platforms. Video quality is decided by the video codec, bitrate, resolution, and whether the file is re-encoded, not by the container alone. The question “MKV vs MP4, which is better?” depends on where you want to play or store the video.

Q2. Will converting MP4 to MKV reduce quality?

If you only change the container and keep the original video/audio streams, there should be no quality loss. If the converter re-encodes the file, quality and file size depend on the chosen codec, bitrate, resolution, and other settings. For a quick quality-preserved conversion, keep the output settings close to the source file.

Q3. How do I batch convert MP4 to MKV?

The easiest way is to use a batch converter such as WonderFox HD Video Converter Factory Pro: add all MP4 files, choose MKV once, select an output folder, and click Run. FFmpeg can also batch remux files with commands, while HandBrake can process multiple files through its queue. Online tools are less suitable for large batches because files need to be uploaded and downloaded.

Q4. What is the free program to convert MP4 to MKV?

• WonderFox Free HD Video Converter Factory (for Windows)
• VLC (for Windows & Mac)
• HandBrake (for Windows & Mac)
• FFmpeg (for Windows & Mac)
• Online converters for small, non-private videos

Q5. Should I convert MP4 to MKV?

Convert MP4 to MKV when you need a more flexible container, such as keeping multiple audio tracks, subtitles, or chapters in one file. Keep MP4 if you need the best compatibility with mobile devices, web upload, social media, or built-in TV players.

Q6. Can I change MKV to MP4?

Yes. You can change videos from MKV to MP4 directly using the tools introduced in this article. The most recommended solution is still WonderFox HD Video Converter Factory Pro, as it can batch convert MKV to MP4 without any limit.
Professional MKV/MP4 video converter free download here:

Sum up

This article shares eight ways to convert MP4 to MKV, including batch, free, command-line, desktop, and online solutions. For many files or quality-preserved conversion, WonderFox HD Video Converter Factory Pro is the most straightforward choice. For occasional small files, VLC, HandBrake, FFmpeg, or an online converter can also help. Choose the method based on your file size, privacy needs, and whether you want to re-encode the video.