MKV to 3GP Converter
Convert MKV to 3GP free — no upload, no signup
To convert MKV to 3GP, drop your MKV video into the box below and click Convert. Fylo converts with ffmpeg running inside your browser, so nothing is uploaded and there's no signup or watermark. Turn MKV clips into small 3GP files for old phones.
Drop videos here
or tap to browse · paste with Ctrl+V · add many at once
Your files never leave your device
If the video already uses codecs that fit the new format, Fylo repackages it instantly with no quality loss.
Advanced
How to convert MKV to 3GP
Add your MKV videos
Drag and drop MKV files into the box or tap to choose them. The converter engine (about 31 MB) downloads once, the first time you convert.
Choose quality (optional)
Balanced quality suits most videos. If the codecs already fit 3GP, Fylo repackages the file instead of re-encoding it, with no quality loss.
Convert and download
Click Convert, then download each 3GP file or all of them as one ZIP.
Why convert MKV to 3GP?
Basic phones can't play Matroska. 3GP gives them a compatible, compact file.
What happens when you convert MKV to 3GP?
The video is re-encoded to H.264 Baseline at up to 720p with 96 kbps AAC audio; files become much smaller.
How does Fylo convert MKV to 3GP?
Fylo reads the MKV with ffmpeg compiled to WebAssembly and writes H.264 Baseline profile capped at 720p with 96 kbps AAC audio. MKV's usual codecs (Any: H.264, HEVC, VP9, AV1…) can't go into 3GP as-is, so the video is re-encoded. Speed depends on your device: short phone clips take seconds, while on our slow test PC a 2-minute 1080p video took about 10 minutes. Only the first video and audio track are kept, and larger videos are scaled down to 720p (or 480p if you choose it).
What's the difference between MKV and 3GP?
MKV is the Matroska container, an open standard first released in 2002. It can hold virtually any video, audio or subtitle codec, and any number of tracks — so one file can carry several languages, director's commentary and subtitles. WebM is a restricted subset of Matroska.
3GP was defined by the 3rd Generation Partnership Project for 3G mobile phones and MMS messaging. It's based on the same ISO media structure as MP4 but restricted to phone-friendly codecs such as H.263 or H.264 Baseline video and AMR or AAC audio.
Learn more: MKV format guide · 3GP format guide
| Property | MKV | 3GP |
|---|---|---|
| Developed by | Matroska project (open standard) | 3rd Generation Partnership Project (3GPP) |
| Introduced | 2002 | 2002 |
| Typical video codecs | Any: H.264, HEVC, VP9, AV1… | H.263, H.264 (Baseline) |
| Typical audio codecs | Any: AAC, Opus, FLAC, DTS, AC-3… | AMR, AAC |
| Plays in web browsers | Partly (Chrome/Edge for some codecs) | Partly |
| Compatibility | VLC, Plex, Kodi, most smart TVs; not iPhone or many editors | Old feature phones, most media players |
| Best for | Movies with multiple audio and subtitle tracks | Very small videos for old phones and MMS |
Frequently asked questions
Can I convert a full movie to 3GP?
Yes, but it takes a long time in the browser. Choose 480p for speed and size.
Which audio track is used?
The first one in the MKV.
Is my MKV file uploaded to a server?
No. Fylo runs ffmpeg, the same engine used by professional video tools, compiled to WebAssembly inside your browser. Your MKV file is read directly from your device and never sent anywhere.
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