How to Convert M4A to MP3 on a Mac

By the M4AtoMP3.org editorial team · October 7, 2026 · 9 min read

Macs are surrounded by M4A files. The Music app imports CDs as AAC by default, Voice Memos records M4A, GarageBand exports it, and AirDropped audio from an iPhone almost always arrives in that format. Most of the time that is fine — but the moment you need to send audio to a Windows user, load a USB stick for a car, upload to a site that only accepts MP3, or feed a DJ or podcast tool, you need MP3. macOS does not make this obvious. Here are three reliable ways to do it, plus a few dead ends you can skip.

The dead ends: QuickTime, Shortcuts and afconvert

It is worth knowing what does not work, because these are the first places most Mac users look.

• QuickTime Player has File › Export As › Audio Only, but it always produces an M4A (AAC) file.
• Shortcuts and Automator offer an Encode Media action whose audio formats are M4A and AIFF — no MP3.
• Finder’s right-click Encode Selected Audio Files service also outputs AAC or Apple Lossless.
• afconvert, the audio tool built into macOS’s Terminal, can read MP3 but has no MP3 encoder.

Apple’s own frameworks do not include an MP3 encoder outside the Music app, so you need one of the methods below.

Method 1: The Music app (built in)

The Music app can create an MP3 copy of any song in your library. It is the only built-in option and keeps your tags and artwork intact.

1. Open Music and choose Music › Settings… (on older macOS: Preferences).
2. Click the Files tab, then Import Settings….
3. Set Import Using to MP3 Encoder.
4. Set Setting to Higher Quality (192 kbps), or choose Custom… and pick 320 kbps for the best quality. Click OK.
5. If your files are not in the library yet, choose File › Import… and select them. (To avoid duplicating files you only want to convert, you can untick Copy files to Music Media folder when adding to Library in the Files settings first.)
6. Select the songs, then choose File › Convert › Create MP3 Version.
7. The new MP3s appear next to the originals. Right-click one and choose Show in Finder to locate the files.

Afterwards, set Import Using back to AAC Encoder if you rip CDs, because the setting applies to all future imports. The Music app cannot convert DRM-protected purchases or tracks downloaded from Apple Music’s streaming catalogue.

Best for: songs already in your Music library, when you want tags and artwork preserved.

Method 2: A browser converter (no setup)

If the files are not music — voice memos, interviews, lectures, GarageBand bounces — importing them into your music library is clumsy. A browser-based converter is quicker.

1. Open the M4A to MP3 converter in Safari, Chrome or Firefox.
2. Drag files from Finder onto the drop zone. Cmd+A in a Finder window selects everything.
3. Choose 128 kbps for speech or 192/320 kbps for music.
4. Click Convert to MP3, then Download all (ZIP). Safari unzips archives automatically by default; otherwise double-click the ZIP in Downloads.

The audio is processed locally by your Mac’s CPU inside the browser — nothing is uploaded — so it works offline once the page has loaded and is safe for private recordings. Safari decodes both AAC and Apple Lossless M4A natively, so conversion starts instantly.

Best for: one-off conversions, voice memos and anything you do not want in your music library.

Method 3: ffmpeg in Terminal (batch and automation)

For large collections or repeat jobs, ffmpeg is the most powerful tool available. The easiest way to install it is with Homebrew:

brew install ffmpeg

Convert one file:

ffmpeg -i "Lecture 3.m4a" -vn -c:a libmp3lame -b:a 192k -map_metadata 0 -id3v2_version 3 "Lecture 3.mp3"

Convert every M4A in the current folder:

for f in *.m4a; do
  ffmpeg -n -i "$f" -vn -c:a libmp3lame -b:a 192k -map_metadata 0 -id3v2_version 3 "${f%.m4a}.mp3"
done

Convert a whole folder tree, writing MP3s next to the originals:

find . -name '*.m4a' -print0 | while IFS= read -r -d '' f; do
  ffmpeg -nostdin -n -i "$f" -vn -c:a libmp3lame -b:a 192k -map_metadata 0 -id3v2_version 3 "${f%.m4a}.mp3"
done

-n skips files that already exist, so re-running is safe; -nostdin stops ffmpeg from swallowing the file list in the loop; -vn ignores embedded artwork streams; and -map_metadata 0 -id3v2_version 3 copies tags in the format most players read best. For variable bitrate at very high quality, replace -b:a 192k with -q:a 0.

Best for: large libraries, scripts and power users.

Which method should you use?

Choosing the right quality

Get Info on a file in Finder (Cmd+I) and look at More Info for its bit rate, or check the Bit Rate column in the Music app. Then choose an MP3 bitrate equal to or higher than the source:

• Voice Memos (compressed): roughly 64 kbps AAC → 128 kbps MP3.
• Typical AAC downloads and podcasts at 128 kbps → 192 kbps.
• iTunes Plus purchases at 256 kbps → 320 kbps.
• Apple Lossless (ALAC) M4A → 320 kbps.

Higher than that only makes the file bigger. If you are unsure, 192 kbps is a sensible default. For more background, read M4A vs MP3 and audio bitrate explained.

Troubleshooting on macOS

“Create MP3 Version” is greyed out. The selected tracks are probably cloud-only or protected. Download them first, or check that they are not Apple Music catalogue tracks (which are DRM-protected and cannot be converted).

The MP3 is in a strange folder. The Music app files MP3 copies under its media folder by artist and album. Use Show in Finder rather than searching.

Safari downloads a ZIP that does not open automatically. In Safari › Settings › General, the option Open “safe” files after downloading controls this. Double-click the ZIP to extract it manually.

Homebrew says “command not found”. Install Homebrew from brew.sh first, then follow the instructions it prints to add it to your shell’s PATH.

Keeping tags and artwork

If your M4A files are part of a music collection, tags matter. The Music app copies all tags and artwork to the MP3 version automatically. ffmpeg copies text tags with -map_metadata 0; to carry embedded cover art across as well, map the picture stream and mark it as an attached picture:

ffmpeg -i in.m4a -map 0:a -map 0:v? -c:a libmp3lame -b:a 192k -c:v copy -disposition:v attached_pic -id3v2_version 3 out.mp3

Browser converters focus on the audio and do not always preserve artwork, so for a polished library, re-tag converted files with the Music app or a tag editor afterwards.

Summary

For music in your library, the Music app’s Create MP3 Version is the built-in answer. For everything else, a browser-based converter is the quickest — and private, because files never leave your Mac. For big libraries, ffmpeg via Homebrew does the job in a single loop. Need the opposite? Our MP3 to M4A converter creates AAC files, for example for iPhone ringtones.

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