Convert MP3 to M4A
To convert MP3 to M4A, add your .mp3 file below and press the button: it's processed on your own device and you download the result, with nothing uploaded. It's free, needs no account, and works with files up to 500MB.
About converting MP3 to M4A
MP3 (.mp3) files can be converted to M4A entirely in your browser — no software to install, no file upload, and no account required. The conversion runs on a WebAssembly build of ffmpeg directly on your device.
Technical comparison
| MP3 | M4A | |
|---|---|---|
| Category | audio | audio |
| Compression type | Lossy | Lossy (AAC), or lossless via ALAC |
| Typical file size | Small — roughly 1MB per minute at 128–192kbps | Small — comparable to MP3 at a given bitrate |
| Transparency support | N/A (audio) | N/A (audio) |
How to convert MP3 to M4A privately
Every step below runs on a WebAssembly build of ffmpeg inside this browser tab. Your .mp3 file is never uploaded to a server — there's no network request carrying it anywhere.
Add your MP3 file
Drag and drop, or click to select, a file (.mp3). It's read straight from disk into browser memory — no upload step exists.
Convert locally
FreePrivateConvert converts it to M4A using a WebAssembly build of ffmpeg, entirely within this browser tab.
Download the result
Save your converted .m4a file. It only ever existed in this tab's memory — closing the tab without downloading discards it completely.
Convert MP3 to M4A with ffmpeg (command line)
Prefer the terminal? This is the exact ffmpeg command this page runs for you:
ffmpeg -i input.mp3 -c:a aac -b:a 192k output.m4a- -i input.mp3
- Your MP3 file.
- -c:a aac
- Encode the audio as AAC.
- -b:a 192k
- Audio bitrate of 192k per second: high quality for AAC.
- output.m4a
- The M4A file to create. ffmpeg picks the container from this extension.
Don't have ffmpeg installed? You don't need it: use the converter at the top of this page. It runs the same conversion on your own device, and your file is never uploaded.
FAQ
- Is my file uploaded anywhere?
- No. Your file is read and processed inside this browser tab and never leaves your device. You can confirm it in your browser's developer tools: the Network tab shows no upload.
- Does converting MP3 to M4A reduce quality?
- AAC is lossy and MP3 was already compressed, so this is a second lossy encode, at 192 kbit/s. That's high enough that most listeners won't notice a difference.
- Is there a file size limit?
- Yes: 500MB per file. There's no account and no limit on how many files you convert.
- What's the difference between MP3 and M4A?
- MP3 (MPEG-1 Audio Layer III) and M4A (MPEG-4 Audio) store data differently. MP3: lossy. M4A: lossy (AAC), or lossless via ALAC. M4A is an MP4-based audio container, almost always holding AAC (or occasionally lossless ALAC) audio — Apple's default for music and voice recordings.
- Why convert MP3 to M4A?
- Common uses for M4A: Music purchased from iTunes/Apple Music; iPhone voice memos and recordings; Podcast production with GarageBand/Logic. AAC inside M4A generally sounds better than MP3 at the same bitrate, thanks to a more modern compression algorithm.
- What MIME type does a .m4a file use?
- audio/mp4, the standard type for MPEG-4 Audio.
- What is the ffmpeg command to convert MP3 to M4A?
- Run: ffmpeg -i input.mp3 -c:a aac -b:a 192k output.m4a. This is the exact command FreePrivateConvert runs for this conversion, so you can use this page instead of installing ffmpeg: it runs the same conversion inside your browser.
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