Converting MKV to MP4 on Windows or Mac

You can convert an MKV file to MP4 using free software on your computer. The most straightforward option is HandBrake, which works on Windows, Mac, and Linux. HandBrake takes the video and audio from your MKV file and rewrites it into MP4 format, which plays on more devices and media players.

The conversion process takes time — usually 30 minutes to several hours depending on the video length and your computer's speed. The file size may change during conversion, and the video quality stays the same unless you deliberately adjust it. Once the conversion finishes, you'll have both the original MKV file and the new MP4 file on your computer.

Key Takeaways

  • HandBrake is a free program that converts MKV files to MP4 and runs on Windows, Mac, and Linux computers.
  • The conversion process requires you to select your MKV file, choose MP4 as the output format, and start the conversion — no technical knowledge needed.
  • Conversion time depends on video length and your computer's processing power, typically ranging from 30 minutes to several hours.
  • Your original MKV file remains unchanged; the MP4 version is saved as a separate file you can move or delete.
  • Online conversion websites exist but upload your video to their servers, so use them only for files you don't mind sharing.

Download and Install HandBrake

Go to handbrake.fr in your web browser. Click the download button for your operating system — Windows, Mac, or Linux. The file downloads to your computer's default download folder.

Once the download finishes, open the file. On Windows, this launches an installer that walks you through setup. On Mac, drag the HandBrake icon into your Applications folder. After installation, open HandBrake from your Applications folder or Start menu. The first time you open it, your computer may ask for permission — click Allow or Yes.

Load Your MKV File and Set Output Format

Open HandBrake. Click the "Open Source" button (usually in the top left). Navigate to the folder where your MKV file is stored and select it. HandBrake reads the file and displays information about it — video length, resolution, audio tracks, and subtitles.

Look for the "Format" or "Container" dropdown menu, usually near the top of the window. Click it and select "MP4" from the list. This tells HandBrake to save the output as an MP4 file instead of keeping it as MKV. You'll see the filename at the bottom change to end in .mp4 instead of .mkv.

Choose where you want the MP4 file saved by clicking the folder icon next to the filename. Select a destination folder — your Desktop or Documents folder works fine. HandBrake will create the new file there when conversion finishes.

Start the Conversion and Wait

Once your MKV file is loaded and MP4 is selected as the format, click the "Start" button. HandBrake begins converting and displays a progress bar showing how much is complete. The window shows estimated time remaining, though this can shift as the conversion runs.

Do not close HandBrake or shut down your computer while conversion is running. You can use other programs, but conversion will be slower if your computer is doing heavy work elsewhere. When the progress bar reaches 100%, HandBrake shows "Encoding Complete" and the new MP4 file appears in the folder you selected.

Check Your New MP4 File

Navigate to the folder where you saved the MP4 file. Right-click it and select "Properties" (Windows) or "Get Info" (Mac) to see the file size and confirm it's an MP4. Try opening it with your default video player to make sure it plays correctly.

If the video plays but audio is missing or subtitles don't show, this usually means HandBrake didn't include those tracks by default. You can convert again and adjust the audio or subtitle settings before starting, or use the MP4 file as-is if you don't need those features. The original MKV file is still on your computer unchanged — you can delete it once you confirm the MP4 works.

Using Online Converters as an Alternative

Websites like CloudConvert, Zamzar, and Online-Convert let you upload an MKV file and download the MP4 result without installing software. You select your file, choose MP4 as the output format, and the website handles the conversion on their servers.

Online converters are useful if you can't install software on your computer or prefer not to. The main drawback is that your video file uploads to someone else's server, so only use this method for videos you don't mind sharing. Most sites delete files after a few hours, but there's always some risk with uploading personal content. File size limits also apply — many free services cap uploads at 500 MB to 1 GB, so large videos may not work.

Troubleshooting Common Problems

If HandBrake won't open your MKV file, the file may be corrupted or use a codec HandBrake doesn't recognize. Try opening it with a different video player first to confirm it plays. If it does play but HandBrake still won't read it, try downloading the latest version of HandBrake from handbrake.fr — older versions sometimes have trouble with newer MKV files.

If the conversion starts but stops partway through, your computer may have run out of storage space. Check how much free space is available on your hard drive — the MP4 file needs roughly the same space as the original MKV. Close other programs to free up memory and try again. If conversion keeps failing at the same point, the MKV file itself may have a problem, and you may need to use a different conversion tool or check the file with another video player.

If the MP4 file plays but looks pixelated or blurry, HandBrake may have reduced the video quality during conversion. This happens when you use the default settings on older computers. You can convert again and adjust the quality settings before starting, or accept the lower quality if file size is more important to you.

Frequently Asked Questions

Will the video quality change when I convert from MKV to MP4?

No, not by default. HandBrake copies the video and audio as-is into the new MP4 container. The quality stays identical unless you deliberately change compression settings before conversion. The file size may change slightly depending on how the audio and video are packaged, but the picture and sound quality remain the same.

Can I convert multiple MKV files at once?

HandBrake has a queue feature that lets you add multiple files and convert them one after another without watching each one. Click "Add to Queue" instead of "Start" after setting up each file, then click "Start" once to begin converting all of them in sequence. Your computer will work through them overnight if needed.

What if my MKV file has multiple audio tracks or subtitle files?

HandBrake shows all audio tracks and subtitle files in your MKV and lets you choose which ones to include in the MP4. Before clicking Start, look for the Audio and Subtitles tabs in HandBrake and select the tracks you want. If you want all of them, make sure they're all checked before conversion begins.

Is it safe to delete the original MKV file after converting to MP4?

Yes, once you've confirmed the MP4 plays correctly and contains everything you need, you can delete the MKV file. Keep both files for a few days first to make sure the conversion worked properly. After that, deleting the original saves storage space on your computer.

Why is my MP4 file larger than the original MKV?

This sometimes happens when the MKV file was heavily compressed. The MP4 format may store the same video and audio less efficiently, resulting in a larger file. You can convert again and enable compression in HandBrake's settings to reduce file size, though this takes longer and may slightly reduce quality.