FLAC vs AIFF: Which Lossless Format Should You Use?

The Short Answer

FLAC and AIFF are both lossless — they sound identical. The difference is packaging: FLAC is compressed (about half the size, with great tags), while AIFF is uncompressed (bigger, and Apple's equivalent of WAV). For storage and libraries, choose FLAC. For audio editing on a Mac or maximum raw-file compatibility, AIFF has a niche. For quality, it's a tie.

Side by Side

Quality: Identical

Both are lossless, so the audio is the same — bit-for-bit after decoding. There is no quality difference between FLAC and AIFF; converting between them changes only the container and file size, never the sound.

The Real Difference: Compressed vs Uncompressed

• AIFF is uncompressed — it stores raw PCM (like WAV), so files are large (~10 MB/min) but need no decoding. That makes AIFF handy inside audio editors, especially on macOS where it's the native uncompressed format.
• FLAC is compressed — same audio, ~40–60% smaller, with a trivial decode step on playback. That makes FLAC the better choice for storing and moving a lossless library.

Think of it as WAV vs FLAC but on the Apple side: AIFF ≈ Apple's WAV, FLAC ≈ the space-saving lossless option.

Which Should You Choose?

• Storing or archiving a lossless library? → FLAC. Half the size, full tags, identical quality.
• Editing audio on a Mac (Logic, GarageBand) or need uncompressed PCM? → AIFF (or WAV).
• Want the most universal lossless format? → FLAC (open, widely supported, small).
• On Apple and want lossless with proper library management? → consider ALAC too. See FLAC vs ALAC.

Converting Between Them (Lossless)

• FLAC → AIFF to feed an Apple editor or a workflow that wants uncompressed PCM. FLAC to AIFF →
• AIFF → FLAC to shrink big uncompressed files for storage without losing quality. AIFF to FLAC →

Both are lossless, so the conversion is exact and reversible — no quality change either way. For the WAV-side equivalent, see WAV vs AIFF.

Frequently Asked Questions

Is FLAC better than AIFF?

In quality, they're equal (both lossless). FLAC is smaller and better for storage; AIFF is uncompressed and handy for editing on Apple. Pick by use case.

Do FLAC and AIFF sound different?

No — both are lossless and contain identical audio. Any difference is placebo.

What's the main difference between FLAC and AIFF?

Compression: FLAC is compressed (smaller); AIFF is uncompressed PCM (larger), essentially Apple's version of WAV.

Can I convert AIFF to FLAC without losing quality?

Yes — both are lossless, so the conversion is exact and reversible.

Which is smaller, FLAC or AIFF?

FLAC — it's compressed, roughly half the size of an uncompressed AIFF at identical quality.

Should I use FLAC or AIFF for editing?

AIFF (or WAV) is convenient for uncompressed editing, especially on Apple software; FLAC is better for storage and delivery.