01
Modern compression standards
MP4 typically achieves better compression efficiency than MKV at equivalent perceived quality. The result is a smaller file that still looks or sounds the same to most listeners and viewers.
100% local
VIDEO
Convert MKV
to MP4
Modern compression standards.
MP4 typically achieves better compression efficiency than MKV at equivalent perceived quality. The result is a smaller file that still looks or sounds the same to most listeners and viewers.
— Drop area
WHY CONVERT
Why convert MKV to MP4
02
Broader cross-platform support
MP4 is accepted by a wider range of video players, mobile devices, and streaming platforms than MKV. The conversion removes a recurring compatibility friction without changing what the file actually contains.
03
Lower storage and bandwidth cost
MP4 files are typically smaller than their MKV counterparts, which reduces hosting, transfer, and storage costs at scale. The savings compound when serving the same content to many recipients.
— How to convert
MKV to MP4 in three steps.
- 01
Open LocalConvert
Visit this page on any modern browser — no install, no signup, no plugin.
- 02
Drop or select your MKV file
Drag your MKV into the drop area, or click to pick one from your device.
- 03
Click Convert
Conversion runs entirely in your browser. When it's done, your MP4 file downloads to your device.
QUALITY & FIDELITY
Quality and fidelity
- If codecs are MP4-compatible (H.264/H.265 + AAC), it's a lossless remux.
- Subtitles and chapters may be dropped if the codec isn't supported in MP4.
- Audio may be re-encoded if FLAC/DTS streams are present.
Transparency MKV
✗ MP4
✗
Color depth any (container) 8/10-bit video, AAC audio
Metadata preserved ✓
FORMAT SPECS
Format specifications
| MKV | MP4 | |
|---|---|---|
| Extensions | .mkv .mka .mks | .mp4 .m4v |
| MIME types | video/x-matroska | video/mp4 |
| Introduced | 2002 | 2001 |
| Maintainer | Matroska / CELLAR (IETF) | ISO/IEC (MPEG-4) |
| Magic # | 1A 45 DF A3 | 00 00 00 ?? 66 74 79 70 |
| Spec | View spec ↗ | View spec ↗ |
COMPATIBILITY
Where these formats work
| Platform | Windows | macOS | iOS | Android | Chrome | Firefox | Safari | Edge |
|---|---|---|---|---|---|---|---|---|
| MKV | Native | App | App | App | — | — | — | — |
| MP4 | Native | Native | Native | Native | Native | Native | Native | Native |
MKV
- Windows
- Native
- macOS
- App
- iOS
- App
- Android
- App
- Chrome
- —
- Firefox
- —
- Safari
- —
- Edge
- —
MP4
- Windows
- Native
- macOS
- Native
- iOS
- Native
- Android
- Native
- Chrome
- Native
- Firefox
- Native
- Safari
- Native
- Edge
- Native
Why LocalConvert
How LocalConvert compares
| Category | LocalConvert | Cloud converters |
|---|---|---|
| PRIVACY | Files never leave your device. The whole pipeline runs in your browser via WebAssembly. | Files travel to a remote server, sit in queue storage, and may be retained for analytics or moderation. |
| COST | Free, no signup, no daily quotas. | Often free for small files; paid tiers for batch / large / commercial use. |
| LIMITS | Limited only by your device's memory and CPU. Multi-GB raw footage OK on desktop. | Typical 100 MB to 1 GB per-file caps, plus rate limits. |
— The formats
From · MKV
Matroska Video
An open, flexible container that can hold virtually any video, audio, and subtitle codec.
Typical uses
Movie archives, multi-language releases, home media.
To · MP4
MPEG-4 Part 14
The most widely supported video container. Pairs efficient compression with broad device compatibility.
Typical uses
Streaming, social media uploads, recording, sharing.
— FAQ
Frequently asked.
Is MKV to MP4 conversion free?
Yes. LocalConvert is completely free, with no signup and no per-file or per-day limits.
Do my files get uploaded anywhere?
No. MKV to MP4 conversion happens entirely inside your browser using WebAssembly — your file never leaves your device.
What's the maximum file size?
There's no fixed cap — the practical limit is your device's available memory. Very large files may take longer or fail on low-RAM devices.
Does it work offline?
Yes — once the page has loaded, MKV to MP4 conversion works without an internet connection. Re-open the page once to cache it.
Will conversion preserve quality?
LocalConvert uses the industry-standard tools (FFmpeg, ImageMagick, Pandoc) — quality matches what professionals use on the command line. Lossy formats will still lose some quality on each re-encode.
— Related
Or convert these.
Browse all conversionsREFERENCES
Format references
Last verified:
100% local conversion.
MKV to MP4 is processed in your browser with WebAssembly. No upload, no tracking, no limits. Your file never leaves your device.