MP4 to MKV Converter
Convert MP4 to MKV in your browser. Free, no signup. Conversion files are not uploaded to Format Convertly servers. Learn the formats, then convert when your workflow needs MKV.
Choose a file or drag and drop
Drop your MP4 file here or
Choose file · Drag & drop · Public file link
- Processed on your device
- No conversion file stored on our servers
- Maximum file size: 100 MB
Conversion runs in your browser. Files are not uploaded to Format Convertly servers.
Processed on your device
No conversion file stored on our servers
Conversion Settings
Customize the output to match your needs.
Convert Quality
92%Output
Output options for this format are applied automatically during browser conversion. Drop your file above to begin.
Advanced settings
Additional Options
Quality or bitrate forces a re-encode. Width/FPS apply only when creating GIF or animated WebP.
How to Convert MP4 to MKV
Add your MP4
Drop a MP4 file into the browser panel. Nothing is sent to a remote queue.
Confirm settings
Review optional quality/size settings, then confirm MKV as the output.
Download MKV
Convert locally and download the MKV file when processing finishes.
Why Convert MP4 to MKV?
Private by design
MP4 → MKV runs in your browser. Files are not uploaded to a remote conversion queue.
Ready for the next step
Convert when a site, editor, or teammate expects MKV instead of MP4.
Practical quality
MKV: codec-dependent. Lossy targets trade size for speed — preview when it matters.
Wide compatibility
MP4 is commonly used for Social uploads and Website video.
MP4 vs MKV
A quick side-by-side before you convert — deeper comparison lives on the full guide.
| Feature | MP4 | MKV |
|---|---|---|
| Playback reach | Excellent | VLC-great; device gaps |
| Multiple audio/subs | Limited vs MKV | Excellent |
| Best for | Delivery | Archival multi-track rips |
| Web support | Excellent | Poor vs MP4 |
| Chapters | Basic | Strong |
| Phone/smart TV | Usually fine | Variable |
| Editing imports | Widely accepted | Some NLEs need convert |
Choose MP4 when…
- Mobile and smart TV playback
- Social and LMS uploads
- Browser video
- Simple single-audio deliveries
Choose MKV when…
- Movies with many subtitle/audio tracks
- Chaptered archival rips
- Keeping commentary tracks
- FOSS container workflows
What happens to video quality?
MKV compatibility: Excellent in VLC and enthusiast players; variable on iOS, some smart TVs, and web players that expect MP4
Tip
Converting from MP4 cannot restore detail already removed by lossy compression.
Does MP4 to MKV reduce quality?
MKV is typically lossy (codec-dependent). Use a higher bitrate when fidelity matters, and keep the MP4 master for archival.
MKV format guide →Should I keep the original MP4?
Yes when you may need to re-encode later. MP4: MP4 is the safest video delivery format for phones, web, and social platforms. Shoot or edit in whatever your camera prefers, then provide an MP4 derivative for sharing.
MP4 format guide →MP4 · MKV
Related converters MP4
Related converters MKV
Frequently Asked Questions
More on quality loss: conversion quality guides · problem-solution guides
Does MP4 conversion reduce quality?
Changing containers can be lossless to quality if streams are copied. Re-encoding to another codec or bitrate can reduce quality.
Can you recover quality after converting?
Not from a lossy output alone. Return to the original master (or a better source). Converting to a lossless format does not resurrect discarded detail.
What is generational loss?
Damage that stacks when you decode and lossy-encode the same file over and over (for example JPG→edit→JPG). Edit from masters and export delivery formats once.
Where can I learn more about conversion quality?
Browse Format Convertly’s Quality guides for topics like whether conversion reduces quality, JPG↔PNG myths, WebP/MP3/MP4 tradeoffs, recovery limits, and generational loss — each links to the right converter.
What is a MP4 file?
MP4 is a ubiquitous multimedia container usually holding H.264/H.265 video and AAC audio. MP4 is the safest video delivery format for phones, web, and social platforms. Shoot or edit in whatever your camera prefers, then provide an MP4 derivative for sharing.
Is MP4 lossy or lossless?
MP4 is typically lossy (lossy (codec-dependent)). That keeps files small but means discarded detail cannot be restored later.
What is a MKV file?
MKV is a Matroska multimedia container that can hold many video, audio, and subtitle tracks. MKV is a flexible open container beloved for rips and multi-track films (commentary, subtitles, multiple audio languages). Convert to MP4 when a device or web platform refuses Matroska.
Is MP4 to MKV private?
Yes. The file is processed locally in your browser and is not uploaded to Format Convertly servers.
Ready to Convert Your Files?
MP4 to MKV privately in your browser.