What happens when you convert MKV to 3GP
- The video is re-encoded to H.264 video with AAC audio at mobile-friendly settings.
- Re-encoding in a browser is slow: expect several times the video's length for HD footage on a laptop, and longer on a phone. Short and low-resolution clips finish much sooner.
How to convert MKV to 3GP online
- Press "Choose MKV files" and select one or more files, or drag them onto the box. You can add files of any size your device can hold in memory.
- Adjust the settings if you need to: resolution and quality control the size of the result. The defaults suit most people.
- Press "Convert to 3GP". The first audio or video conversion downloads the converter engine, about 32 MB, which your browser then keeps for next time.
- Save each 3GP with its download button. Close the tab and every trace of the files is gone from memory.
Why convert MKV to 3GP?
MKV files usually come from films and TV rips, OBS recordings and anime releases. People convert them to 3GP because 3GP files are small enough for very old phones and low-bandwidth connections.
In short, MKV is good at what it was made for, and 3GP is the more practical choice when the file has to play, upload or edit somewhere else. Chrome and Edge play many MKV files; Safari and iPhones do not, while 3GP plays in some browsers and most phones.
How to convert MKV to 3GP on Windows, Mac, iPhone and Android
On Windows
Open this page in Chrome, Edge or Firefox, drag your MKV files in from File Explorer, and press Convert. Each 3GP is saved to your Downloads folder. If you prefer a desktop program, VLC can also convert MKV to 3GP: choose Media, then Convert / Save.
On a Mac
Safari, Chrome and Firefox all work. Drag the MKV files from Finder onto the drop zone and the 3GP files land in Downloads.
On iPhone and iPad
Open the page in Safari and tap Choose MKV files. You can pick from Photos or from the Files app. The converted 3GP appears in Files, in the Downloads folder; to put it in your photo library, open it there, tap Share and choose Save Video.
On Android
Open the page in Chrome, tap Choose MKV files and pick them from Files or your gallery. The 3GP is saved to the Download folder, where any file manager can find it. Keep the screen on while a long video converts, because Android may pause a tab in the background.
Best settings for MKV to 3GP
3GP is written as H.264 video with AAC audio at mobile-friendly settings. The Resolution setting is the one to reach for: 1080p keeps full HD detail, 720p is plenty for phones and laptops and roughly halves the size, and 480p suits email and old devices.
The quality levels map to the H.264 CRF scale where the target uses H.264, and to fixed high-quality settings for older codecs such as MPEG-2, MPEG-4 Part 2, WMV and Theora. Re-encoding always costs a little detail, so convert from the best copy of the MKV you have.
MKV vs 3GP: the differences
| MKV | 3GP | |
|---|---|---|
| Full name | Matroska video | 3GPP multimedia file |
| Type | video | video |
| Created by | the Matroska project | the 3rd Generation Partnership Project |
| First released | 2002 | 2003 |
| Compression | Lossy | Lossy |
| Usually contains | almost any codec, often H.264 or H.265 with several audio and subtitle tracks | H.263 or H.264 video with AMR or AAC audio |
| In a browser | Chrome and Edge play many MKV files; Safari and iPhones do not | plays in some browsers and most phones |
| Common uses | films and TV rips, OBS recordings and anime releases | videos from older feature phones and early smartphones |
| MIME type | video/x-matroska | video/3gpp |
About MKV and 3GP files
What is an MKV file?
MKV can hold unlimited audio tracks, subtitle tracks and chapters in one file, which is why film rips use it. OBS offers MKV recording because a crash part way through does not corrupt the whole file.
What is a 3GP file?
3GP was built for 3G phones with small screens and slow connections, so most files are 176 by 144 or 320 by 240 pixels. Converting to a modern format will not add detail that was never recorded.
MKV to 3GP not working? Common problems
- The conversion is slow. Audio and container changes take seconds, but re-encoding video runs on your own processor. Lower the resolution to 720p, close other tabs, and keep the device plugged in.
- The tab stops or reloads on a very large file. Browsers limit how much memory one tab can use, around 2 GB and less on phones. Split long recordings or convert them on a computer.
- The 3GP will not play on an old device. Try the other formats offered for MKV, or choose 720p, which older players handle more reliably.
Convert MKV to 3GP with ffmpeg
This converter runs ffmpeg inside your browser. If you would rather use the ffmpeg command line on your own computer, this command produces an equivalent 3GP with the same kind of settings:
ffmpeg -i input.mkv -c:v libx264 -profile:v baseline -c:a aac -b:a 96k output.3gpReplace input.mkv with the name of your file. For a whole folder of MKV files, run the command in a loop, or drop them all on the converter above, which processes them one after another.
MKV to 3GP converter FAQ
Will I lose quality converting MKV to 3GP?
A little. Both formats are lossy, so re-encoding compounds the loss slightly. Keep the default quality or higher and the difference is rarely noticeable.
Why is the 3GP a different size from the MKV?
It depends on the settings. At the defaults, the 3GP usually comes out close in size to the MKV; lower the quality for a smaller file.
Are my MKV files uploaded anywhere?
No. The conversion runs inside this browser tab using ffmpeg compiled to WebAssembly, so your files stay on your device. You can disconnect from the internet after the page and converter engine have loaded and it still works.
Can I convert several MKV files to 3GP at once?
Yes. Select or drop as many files as you like; they are converted one after another and each gets its own download button.
How do I open a 3GP file?
3GP plays in some browsers and most phones. 3GP is common for videos from older feature phones and early smartphones.
Is this MKV to 3GP converter free?
Yes. There is no sign-up, no watermark and no limit on how many files you convert. The site is paid for by advertising, and because conversions run on your device there is no server cost per file.
Can I convert MKV to 3GP on my phone?
Yes. The converter works in Safari on iPhone and iPad and in Chrome on Android. Long HD videos convert more slowly on a phone than on a computer.