Step 1: Drop your 3GP files using the button above or by deposit and leave.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Receive your converted MKV files.
3GP to MKV Conversion FAQ
Is the 3GP to MKV converter free?
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Yes. One conversion an hour is free, with no account needed, for a file within the free size limit. A paid plan removes the hourly limit and the size limit, and lets you add several files to one job.
Can I add selectable subtitles once the file is MKV?
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Yes. 3GP has no usable soft-subtitle track, so subtitles for 3GP content had to be burned into the picture or shipped as a separate sidecar file. MKV carries subtitles as their own selectable stream, so after conversion you can attach an SRT track the viewer can switch on, switch off or restyle. MKV is codec-agnostic: H.264, HEVC, VP9 and AV1 video sit happily beside AAC, FLAC, Opus, DTS or Dolby audio in the same file.
Can the MKV hold more than one audio track?
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Yes, and it is a real upgrade over 3GP. MKV treats every audio stream as a first-class track, so an original-language mix, a dub and a director commentary can live in one file with the player switching between them on demand. MKV is the archival container of choice because it stores unlimited audio tracks, soft subtitles, chapter markers and cover art in one file.
Does MKV support chapter markers that 3GP did not?
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It does. MKV stores chapters as container metadata, so a long recording can be navigated by section instead of by scrubbing a progress bar. 3GP has nowhere to put that information, so the converted MKV starts with no chapters; add markers afterwards with a tool such as MKVToolNix or ffmpeg.
Will the MKV still play smoothly on a phone or a TV?
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It may not. 3GP is decoded by dedicated silicon on phones, tablets and TVs, which is why it plays without flattening the battery. MKV typically falls back to software decoding on the same hardware — higher CPU load, a warmer device, and dropped frames on 4K material. For a device target, 3GP is the safer container to stay in. MKV has almost no native hardware support — phones, browsers and TVs usually need VLC or a remux before they will play it.
Both 3GP and MKV are modern containers — which should I actually keep?
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Keep whichever matches where the file is going, because neither is better in the abstract. One of these two is built for playback compatibility and the other for holding everything a file might contain, and they trade against each other exactly along that line. The pragmatic answer for most libraries is to archive in the feature-rich container and export to the compatible one on demand. 3GP files are tiny and decode on the weakest hardware imaginable, which is why feature phones and low-end handsets still record it.
How big a 3GP file can I convert to MKV?
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Free conversions have a size limit per file, set by the type of file, and the page tells you when a file is over it. A paid plan removes that limit, so much larger files can be converted.
Can I convert many 3GP files to MKV at once?
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Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.
Does the 3GP to MKV converter work on phones and tablets?
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Yes — the UI is responsive and the conversion pipeline runs server-side, so mobile devices upload-then-download just like desktops. iOS and Android browser file pickers (camera roll, Files app) work end-to-end.
Which browsers does the 3GP to MKV converter support?
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Chrome, Firefox, Safari (15+), Edge, and Opera. The converter uses standard `<input type="file">` upload — no WebAssembly or PWA dependencies — so even older browsers work.
