Add files from where they live
Drop a MKV file on the box, browse for it, or import it from Dropbox, Google Drive or a link. You can add more files later, and each file gets its own result.
Free MKV to MP4 converter
Convert MKV to MP4 online. Add a file, confirm MP4 and download it. A single file needs no account.
Converting MKV to MP4 trades Matroska's flexibility for a file that iPhones, televisions, consoles and browsers will play. The main video and audio normally come across. What may not are the extras: MP4 holds fewer subtitle formats and players handle fewer tracks, so additional languages, styled subtitles and chapters can be dropped.
Transfers use HTTPS, and files converted on the free tier are deleted within 24 hours, so the result is not a long-term archive. Quality depends on the source file, so open the MP4 file once before you share it.
FromMKVLossy
MKV (Matroska Video)
An open, royalty-free container from the Matroska project, first released in 2002. One file can hold almost any codec plus many audio tracks, subtitle tracks, chapters and attachments such as fonts, which makes it popular for film rips and recordings.
ToMP4Lossy
MP4 (MPEG-4 Part 14)
A stricter container defined by the MPEG standards group. It expects a narrow set of codecs and offers only limited text subtitle support, and in exchange it gets hardware playback on iPhones, consoles, televisions and browsers that often reject Matroska.
Why use indox to convert MKV to MP4?
Watch the job run
A progress bar shows the file moving through the conversion. If you picked the wrong file, cancel and start again.
Download it or hand it on
Save the MP4 file, copy a share link or convert it to another format. Free-tier output expires on its own after 24 hours.
What changes
- Subtitle support narrows sharply. MP4 carries simple timed text, so image-based PGS and VobSub tracks from discs and styled ASS subtitles with fonts and positioning do not fit as they are.
- Multiple tracks become less dependable. An MKV may bundle several dubs and a commentary, and although MP4 can store more than one audio stream, many players only offer the first.
- Audio often needs changing. DTS, TrueHD and FLAC are common in Matroska files but poorly supported by MP4 players, so such tracks are usually converted to AAC.
- Device support improves. Apple's players, many smart TVs, game consoles and web browsers that reject or only partly support Matroska accept MP4 without extra software.
How do I convert MKV to MP4 online?
- 1
Add your MKV file
Drop your MKV file into the converter (or choose a file from disk).
- 2
Pick MP4 and press Convert
Confirm MP4 as the output format and start the conversion.
- 3
Download the MP4 file
Download the MP4 file when it is ready. Start another conversion anytime.
What do I get from indox's MKV to MP4 converter?
You upload a MKV file, indox converts it to MP4, and you download the result. A single file needs no account, and nothing is installed.
- No install and no account for a single file
- MP4 output you can download or share
- Progress while the job runs, with a cancel button
- Free-tier files are deleted within 24 hours
What are the limits for MKV to MP4?
Size
The upload box shows the live size limit before you add a file. Signing in raises it, and paid plans raise it further.
Formats
MKV in, MP4 out. Pick another output on the converter if you need a different format.
Privacy
Files are encrypted in transit over HTTPS and processed on indox infrastructure.
Deletion
Free-tier files are deleted automatically within 24 hours after the job finishes.
Limits worth knowing
- Subtitles are the usual casualty. Picture-based and heavily styled tracks cannot be stored as MP4 text, so they may be missing unless burned into the image.
- Whether quality is preserved depends on the codecs inside. H.264 or HEVC video could be copied unchanged, while less common formats may need a lossy re-encode.
- Attachments, including the fonts that styled subtitles rely on, and ordered or nested chapter structures have no MP4 counterpart.
- Surround sound in DTS or TrueHD may be reduced to a format with fewer channels or lower fidelity, depending on how the audio is converted.
What do the free and paid plans add?
Free
- All converters
- Daily credit refresh
- Email support
Basic
- Access to all features
- AI Extract & Doc Chat
- Priority conversions
- Email support
Highest priority
Premium
- Everything in Basic
- Highest priority queue
- Larger file limits
- Priority support
Pay-As-You-Go
- No subscription
- Credits never expire
- Opt-in auto-refill
- Access to all features
Which conversions are close to MKV to MP4?
AVI to MP4
Older video files at a smaller size
MOV to MP4
iPhone and Mac video that plays anywhere
WEBM to MP4
Browser recordings you can share
MP4 to MP3
The sound from a video
Related conversionsReverseMP4 to MKV
Who can use a MKV to MP4 converter?
When to use it
- Playing a film on an iPhone, iPad or Apple TV, none of which open MKV in their built-in apps.
- Importing an OBS screen recording or stream capture into a video editor that will not read Matroska.
- Sharing a clip through a messaging app or website that previews MP4 inline but treats MKV as a download.
- Loading a video library onto a television or console whose media player skips MKV files.
Where can I read more about converting files?
Do it all with indox
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MKV to MP4 FAQs
Does converting MKV to MP4 lose quality?
Not necessarily. Both are containers, and when the MKV already holds H.264 or HEVC video with AAC audio, those streams can in principle be moved into MP4 bit for bit. Quality only drops when a stream has to be re-encoded because MP4 players would not handle it, which is most often the audio track.
Will my subtitles be kept when I convert MKV to MP4?
Plain text subtitles such as SRT have the best chance, because MP4 has a timed-text track type they map onto. Blu-ray PGS and DVD VobSub subtitles are images, and ASS subtitles depend on styling and fonts, so neither fits the MP4 text model. Expect those to be dropped, simplified to bare text, or needing to be burned in.
Why won't my TV or iPhone play MKV?
Because the manufacturer chose not to support the container, or supports only some of what it can hold. Apple's built-in players do not read Matroska at all. Many televisions open MKV but then fail on a DTS soundtrack or a subtitle type, giving video with no sound. MP4 with H.264 and AAC avoids both problems.
What happens to multiple audio tracks and languages?
They may not all survive. MP4 is able to store several audio streams, but support in players is uneven, and a conversion may keep only the default track. If you need a particular language or the commentary, check which track plays in the result. The same caution applies to chapters, which MP4 handles in a more limited way.
Is MKV better than MP4?
Neither is better in picture quality, since the container does not determine how the video looks. MKV is the more capable box, with room for any codec, unlimited tracks and rich subtitles, which suits archiving. MP4 is the more playable one. The usual pattern is to keep MKV as the master and make MP4 copies for devices.
Can I rename .mkv to .mp4 instead of converting?
No, that does not work. Matroska and MP4 arrange their data in completely different structures, so a renamed file is still Matroska and most players that refused it before will refuse it again. A few programs inspect the contents and ignore the name, which can make renaming look successful on one machine and fail on the next.