How to Convert AIFF to M4A

AIFF (Audio Interchange File Format) was created by Apple in 1988 as a high-quality audio container for the Macintosh. Logic Pro, GarageBand, and older versions of iTunes all default to AIFF for uncompressed audio. It is functionally equivalent to WAV — both store raw PCM audio — but AIFF stores metadata using a different structure and is traditionally preferred on macOS systems. AIFF files recorded at 24-bit, 44.1 kHz run approximately 15 MB per minute for stereo audio. For a 60-minute album, that means nearly 1 GB of storage before any processing. Converting the final master to M4A is the standard delivery step for consumer distribution.

GarageBand on macOS exports finished projects as AIFF by default when you choose Share > Export Song to Disk and select AIFF. This gives you the uncompressed master. From there, convert to M4A using AudioUtils: drag the exported AIFF file onto the converter, select M4A output, choose 256 kbps AAC for quality listening or 192 kbps for standard delivery, and download the result. The M4A file can then be imported into iTunes (or the Music app on macOS Ventura and later) for syncing to iPhone. GarageBand on iPhone and iPad also exports in M4A format natively — if you want to archive the lossless version, export to iCloud Drive as AIFF first.

Open AudioUtils in Safari on your Mac — the WebAssembly engine works natively in Safari without any plugins. Drag your AIFF file from Finder onto the converter interface. AIFF files can be large; a 5-minute uncompressed track at 24-bit/44.1 kHz is around 75 MB. The conversion happens entirely in your browser memory — processing a file this size takes 10–30 seconds on a modern Mac. Select M4A as the output format. For album masters destined for personal listening, 256 kbps is the recommended bitrate. For streaming platform delivery, check the platform's spec: Apple Music accepts AIFF directly, while Spotify and YouTube Music accept M4A at 256 kbps or higher. Click convert and save the file.

After converting to M4A, importing to iTunes or the Music app is straightforward. On macOS, drag the M4A file onto the Music app window or use File > Import. On Windows, iTunes accepts M4A files identically. The Music app will recognize the AAC codec inside the M4A container and add the file to your library with full metadata support. ID3 tags written to the M4A file (title, artist, album, artwork) will display correctly. If you are importing multiple converted files, select all of them and import in one batch — this is faster than individual imports and preserves album metadata groupings. After import, the original AIFF masters can be archived to an external drive.

The AIFF-to-M4A conversion is always a lossy step. Never convert your AIFF master and then discard it — keep the AIFF as the archive. Future formats, higher-quality encoders, or different delivery requirements will all be better served by reconverting from the lossless AIFF than from a compressed M4A. For mastering engineers: if a client delivers AIFF and you need to send them M4A for approval, encode at 320 kbps so they are hearing something very close to the master. For final consumer release, 256 kbps matches Apple Music's streaming quality. At 256 kbps, the AAC codec's quality is sufficient that the majority of listeners — including many audio professionals — cannot reliably identify it as compressed in a blind test.