Convert MP4 to MKV Online

Convert MPEG-4 Video (.mp4) files to Matroska Video (.mkv) format online for free. Fast, secure, and no sign-up required. Your files are automatically deleted within 1 hour.

Free online mp4 to mkv converter — no software needed. Instantly change, transform, and export your files in seconds.

Coming Soon

MP4 to MKV is coming soon

We're working hard to bring you this tool. Stay tuned for updates — it will be available shortly!

How to Convert MP4 to MKV Online

1. Upload Your File

Select or drag your .mp4 file into the converter

2. Convert Instantly

Your file is converted from .mp4 to .mkv in seconds

3. Download Result

Download your converted .mkv file to any device

Best Free MP4 to MKV Converter

Lightning Fast Conversion

Convert .mp4 to .mkv in seconds. No waiting, no queues — instant processing.

100% Secure & Private

All files are encrypted in transit via HTTPS and auto-deleted within 1 hour. Your data stays private.

Works on Any Device

Browser-based converter — works on Windows, Mac, Linux, iOS, Android, and Chromebook. No installation needed.

No Sign-Up Required

Start converting immediately. No registration, no email, no watermarks on your converted files.

When to Convert MP4 to MKV

MP4 to MKV for Business

Professionals frequently need to convert mp4 files to mkv format for reports, presentations, and document sharing. Our converter preserves formatting and layout perfectly.

Student & Academic Use

Students and researchers can quickly convert mp4 to mkv for assignments, thesis papers, and academic submissions that require a specific file format.

MP4 to MKV for Personal Use

Whether you're organizing personal documents or sharing files with friends and family, converting mp4 to mkv has never been easier with our free online tool.

Cross-Platform Compatibility

Need your mp4 file to work on a different device or operating system? Convert it to mkv to ensure compatibility across Windows, Mac, iOS, Android, and Linux.

MP4 vs MKV — Why Convert?

MP4 (MP4)

Standard MP4 file format
Widely used across platforms
MP4 files may have specific features
May require specific software to open

MKV (MKV)

MKV format for broader compatibility
Easy to share and distribute
Supported by many applications
Ideal for your target workflow

MP4 to MKV — Frequently Asked Questions

Is MP4 to MKV conversion free?

Yes! Reformat offers free MP4 to MKV conversion. Free users get 3 conversions per day. Upgrade to Pro for unlimited conversions.

How do I convert .mp4 to .mkv?

Simply upload your MP4 video, click Convert, and download your MKV video. The entire process takes just seconds.

What is the maximum file size?

Free users can convert files up to 10MB. Pro users get up to 100MB, and Business users get up to 500MB.

Is my file safe?

Absolutely. All files are processed securely and automatically deleted from our servers within 1 hour. We never access or share your data.

Can I convert multiple files at once?

With a Pro or Business account you can batch convert multiple files. Free users can convert one file at a time.

How do I convert MP4 to MKV?

Simply upload your mp4 file to our converter, click "Convert", and download your mkv file. The entire process takes just a few seconds and works directly in your browser.

Is the MP4 to MKV converter free?

Yes! Our mp4 to mkv converter is completely free. Free users get 3 conversions per day. Upgrade to Pro for unlimited conversions and larger file support.

Can I convert MP4 to MKV without installing software?

Absolutely. Our mp4 to mkv converter works 100% online in your web browser. No software downloads, no plugins, no registration required.

Is it safe to convert MP4 to MKV online?

Yes. All files are encrypted during transfer using HTTPS, processed securely on our servers, and automatically deleted within 1 hour. We never access, read, or share your data.

What is the maximum file size for MP4 to MKV conversion?

Free users can convert files up to 10MB. Pro users can convert files up to 100MB, and Business users up to 500MB.

Does the mp4 to mkv converter preserve formatting?

Yes, our converter is designed to preserve the original formatting, layout, images, tables, and text styling as accurately as possible during the conversion.

Can I convert multiple mp4 files to mkv at once?

Pro and Business accounts support batch conversion, allowing you to convert multiple mp4 files to mkv simultaneously. Free users can convert one file at a time.

What devices support the MP4 to MKV converter?

Our converter works on all modern devices and operating systems — Windows, Mac, Linux, iOS, Android, and Chromebook. Any device with a web browser will work.

How long does MP4 to MKV conversion take?

Most conversions complete in under 10 seconds. Larger or more complex files may take slightly longer, but our converter is optimized for speed.

What's the difference between MP4 and MKV files?