Convertlova
MP4MKV

MP4 to MKV Converter
Best Free Online Tools

Compare the top 12 curated tools for converting .mp4 files to .mkv. No scrolling through 50 sketchy sites — pick a tool in 5 seconds.

MP4 to MKV · Video

Convert MP4 to MKV online — free, in your browser

Need to convert a .mp4 file to .mkv? You're in the right place. Convertlova has hand-picked 12 MP4 to MKV converters so you don't have to dig through 50 sketchy results on Google. Every tool below is tested for whether it's truly free, requires signup, adds a watermark, and how fast it actually runs in 2026.

The best free MP4 to MKV converters work entirely in your browser — you upload your .mp4 file, the tool processes it (most are done in seconds), and you download the converted .mkv. No software to install, no sign-up wall, no email harvesting. We've ranked each video converter by free pricing, no watermark, no signup, and output quality, so the top pick at the top of the list is almost always the one you want.

Why convert MP4 to MKV?

  • Compatibility — open your video file in apps and devices that don't support .mp4 natively.
  • Smaller file size — .mkv is often more efficient for sharing, uploading, or embedding on the web.
  • Editing — many editors only accept .mkv files, so converting is a one-step unlock.
  • Quality preservation — the right converter keeps your file looking and sounding exactly like the original.

What to look for in a MP4 to MKV converter

Most online converters technically work, but the experience varies wildly. The four things that actually matter:

  1. Truly free — not "free trial" or "free up to 1 file/day." Filter by Free above.
  2. No signup — you shouldn't need an account to convert one .mp4 file.
  3. No watermark — the converted .mkv should be indistinguishable from a paid output.
  4. Fast and private — files should be processed quickly and deleted from servers after.

How to convert MP4 to MKV in 3 steps

  1. Pick the top-ranked MP4 to MKV tool from the comparison above (or filter by your priority — free, no signup, fastest).
  2. Click Open tool, drag in your .mp4 file, and start the conversion.
  3. Download the converted .mkv file. Done — most video conversions finish in under 30 seconds.
Filter:Showing 12 of 12 tools
Top pick
#1

EditClips Video Converter

editclips.online
Free
No signupNo watermarkFastStandard

Limits: Runs 100% in browser, no upload

Fast and private video conversion.

Open tool
#2

Format Factory

pcfreetime.com
Free
No signupNo watermarkFastStandard

Limits: Desktop software

Popular batch converter for Windows

Open tool
#3

Apowersoft Free Online Video Converter

apowersoft.com
Free
No signupNo watermarkStandardStandard

Limits: Fast online conversion

Reliable tool from a well-known software developer.

Open tool
#4

FFmpeg

ffmpeg.org
Free
No signupNo watermarkStandardStandard

Limits: Command-line tool, requires technical knowledge

Powerful multimedia framework, industry standard

Open tool
#5

FileConverto

fileconverto.com
Free
No signupNo watermarkStandardHigh

Limits: Max 100 MB per file. No daily limit. No watermarks, no signup. Files deleted after 30 minutes.

Minimal design, fast conversions. Supports many rare combinations like WebP to icon and e-book to PDF.

Open tool
#6

HandBrake

handbrake.fr
Free
No signupNo watermarkStandardStandard

Limits: Desktop software, batch processing

Open-source video converter, excellent for video transcoding

Open tool
How it works

How to convert MP4 to MKV

  1. 1

    Pick a tool from the comparison above. We've ranked them by being free, no-signup and no-watermark.

  2. 2

    Open the tool's website (we link directly — never an affiliate cloak).

  3. 3

    Upload your .mp4 file. Most tools accept drag-and-drop.

  4. 4

    Download the converted .mkv file. That's it.

Why convert

MP4 vs MKV — when to convert

.mp4 and .mkv are both video formats. You typically convert when you need:

  • Broader compatibility across apps and devices
  • Smaller file size for sharing or web
  • Different quality / feature tradeoff (transparency, lossless, animation)
  • Editing in software that only opens .mkv

Related conversions

Other ways to convert .mp4 or to .mkv.

MP4 → AVIMP4 → MOVMP4 → MP3MP4 → GIFMP4 → WEBMAVI → MKVMOV → MKVWEBM → MKV

FAQ

What is the difference between MP4 and MKV?

MP4 and MKV are both video formats. Conversion is generally needed when you want broader compatibility, smaller file size, or different quality/feature tradeoffs (transparency, animation, lossless vs lossy, etc.).

Is converting MP4 to MKV safe?

Yes — the tools listed here are reputable browser-based converters or trusted desktop apps. We flag tools that require signup, add watermarks, or have file-size limits so you can pick a fully free, no-strings option.

Will I lose quality converting MP4 to MKV?

It depends on the formats. Lossless-to-lossless conversions preserve quality. Lossy-to-lossy or lossless-to-lossy may reduce fidelity. Look for tools labeled "lossless" in the comparison above when quality matters most.

Can I convert MP4 to MKV offline?

Yes — several listed tools are open-source desktop apps that work offline. Use the "All tools" page to find offline-capable options.