How to Convert M4A to MP3 on Mac: 3 Easy Methods

M4A is the default audio format on Mac and iPhone. Apple Music creates M4A files. Voice Memos saves as M4A. GarageBand exports M4A. If you need MP3 for compatibility with non-Apple devices or software, here are three ways to convert on Mac.

What Is M4A?

M4A is an MPEG-4 Audio container, almost always holding AAC-encoded audio. It is technically identical to AAC in terms of audio quality. The .m4a extension just specifies it is audio-only (as opposed to .mp4 which may contain video). Apple uses it everywhere.

Method 1: Music App (Built-In, No Downloads)

The Music app can create MP3 versions of tracks already in your library:

1. Open Music on your Mac 2. Go to Music menu > Settings 3. Click Files tab, then Import Settings 4. Change "Import Using" dropdown to MP3 Encoder 5. Set Quality to High Quality (192 kbps) or Custom for 320 kbps 6. Click OK to close both dialogs 7. In your library, right-click the M4A track 8. Select Create MP3 Version

Music creates an MP3 copy alongside the original M4A. Both stay in your library. Find the MP3 file in Finder by right-clicking it and selecting Show in Finder.

This only works for files in your Music library. For files on your desktop or Downloads folder, use Method 2.

Method 2: AudioUtils in Browser

Open Safari and go to AudioUtils. Drag your M4A file onto the converter. Select MP3 output. Set bitrate. Click Convert. The MP3 downloads to your Downloads folder.

This works on any M4A file anywhere on your Mac, with no library import required. Conversion is fast on Apple Silicon Macs -- a four-minute song typically converts in under five seconds.

Choose 256 kbps or 320 kbps for music files. For voice recordings or podcasts, 128 kbps is sufficient.

Method 3: Automator for Batch Conversion

For converting many M4A files at once:

1. Open Automator (find it in Applications) 2. Choose New Document > Quick Action 3. Set "Workflow receives current" to audio files in Finder 4. Add action: Encode Media from the library 5. Set format to MP3 and choose quality 6. Save the workflow with a name like "Convert to MP3"

Now right-click any group of M4A files in Finder, go to Quick Actions, and your converter appears. This is the fastest batch method for regular use.

Bitrate Guide for M4A to MP3

M4A files from Apple Music are 256 kbps AAC. This is excellent quality. When converting to MP3:

• 128 kbps MP3: Noticeably worse than source, only for size-critical situations
• 192 kbps MP3: Good quality, reasonable file size
• 256 kbps MP3: Close to source quality, recommended
• 320 kbps MP3: Best MP3 quality, slight overkill for 256 kbps AAC source but safe choice

AAC is more efficient than MP3 -- 256 kbps AAC sounds roughly equivalent to 320 kbps MP3. So even at 256 kbps, your converted MP3 may sound marginally different from the original.

Voice Memos M4A Files

Voice Memos on iPhone saves recordings as M4A at 32 kbps AAC (for standard quality) or up to 256 kbps for lossless. When converting Voice Memos to MP3:

• For 32 kbps source: output at 64 kbps MP3 (going higher wastes space without improving quality)
• For high-quality Voice Memos: output at 128 kbps MP3

GarageBand M4A Exports

GarageBand exports at 256 kbps AAC by default. For GarageBand projects you want to share widely, convert to 256 kbps or 320 kbps MP3. Alternatively, export directly from GarageBand to MP3 via Share > Song to Music > and then use the Music app export method.

Finding the Converted Files

After using the Music app method, right-click the new MP3 in your library and select Show in Finder. Files are typically stored in ~/Music/Music/Media.localized/ sorted by artist and album. From Finder you can move them wherever you need.