Audio Format Comparison

ALAC vs AAC: Apple Lossless vs Lossy Audio

ALAC (Apple Lossless Audio Codec) and AAC (Advanced Audio Coding) are both Apple-ecosystem formats, but serve different purposes. ALAC preserves every sample of the original recording at the cost of larger files. AAC discards perceptually inaudible information to achieve 5–8× smaller files with near-identical perceived quality. For most listening, AAC at 256 kbps is the practical winner; for audiophile archiving, ALAC is the gold standard.

ALACvsAAC

Quick Verdict

Use ALAC when…

Use ALAC when you want bit-perfect audio quality in Apple's ecosystem — for archiving, high-fidelity listening on audiophile equipment, or when storage space is not a concern.

Use AAC when…

Use AAC at 256 kbps for everyday listening, syncing to iPhone, and Apple Music streaming — the quality difference from ALAC is imperceptible to most listeners and files are 5–8× smaller.

ALAC vs AAC: Feature Comparison

Feature	ALAC	AAC
Compression type	Lossless	Lossy
Audio quality	Bit-perfect original	Excellent at 256 kbps
File size (4-min song)	~22–35 MB	~5–8 MB at 256 kbps
Apple Music support	Lossless tier (explicit ALAC stream)	Default for all tiers
iPhone storage impact	High	Low
Bluetooth streaming	Cannot transmit lossless (AAC Bluetooth max)	Native (AirPods, Beats)
Lossless to lossy conversion	Re-encode to AAC any time	Cannot recover ALAC quality
Hi-Res support	Up to 24-bit/192 kHz	Up to 24-bit/192 kHz (Apple Music)

When ALAC wins

✓Compression type: Lossless
✓Audio quality: Bit-perfect original
✓File size (4-min song): ~22–35 MB

When AAC wins

✓Compression type: Lossy
✓Audio quality: Excellent at 256 kbps
✓File size (4-min song): ~5–8 MB at 256 kbps

Frequently asked questions

Can I hear the difference between ALAC and 256 kbps AAC?

In double-blind listening tests, virtually no one can reliably distinguish ALAC from 256 kbps AAC, including trained audio engineers. The quality difference exists mathematically but is below the threshold of human perception for music. ALAC matters most when you need to re-encode to another format in the future — lossless sources re-encode better.

Does Apple Music stream ALAC?

Yes, Apple Music's Lossless tier (included in all subscriptions) streams ALAC at CD quality (16-bit/44.1 kHz). Hi-Res Lossless streams at up to 24-bit/192 kHz. The standard AAC stream is 256 kbps. On iPhone, lossless requires a wired connection or Apple's Lightning/USB-C to 3.5mm adapter.

Should I store my music library as ALAC or AAC?

Store masters in ALAC (or FLAC) — lossless archives can be re-encoded to any format later without quality loss. Use AAC for device copies and syncing. With iCloud Music Library, Apple can serve either based on your settings. Never delete lossless masters.