Short version: FLAC and ALAC sound identical. Both are lossless. Both preserve every single bit of the original recording. The difference is purely about which devices and software support them natively.

If that’s all you needed to know, you can stop reading. If you want the full breakdown, here it is.

What FLAC Is

FLAC stands for Free Lossless Audio Codec. It’s an open standard maintained by the Xiph.org Foundation (the same people behind OGG Vorbis and Opus). FLAC is the default lossless format basically everywhere outside Apple’s ecosystem — Android, Windows, Linux, most portable audio players, and pretty much every music download store that offers lossless.

When you buy lossless downloads from Bandcamp, Qobuz, or HDtracks, FLAC is usually the default option. It’s the format most people rip their CDs to, and it’s what you’ll find on most music forums and archives.

What ALAC Is

ALAC stands for Apple Lossless Audio Codec. Apple developed it in 2004 and open-sourced it in 2011, so technically anyone can implement it. In practice, it’s mainly used within Apple’s ecosystem.

Apple Music, iTunes, the built-in iOS Music app, AirPlay, HomePod — all of these support ALAC natively. When Apple added lossless streaming to Apple Music in 2021, they used ALAC as the codec. If you rip CDs in iTunes, ALAC is one of the format options.

Audio Quality: Identical

I need to be blunt about this because forum arguments about FLAC vs ALAC “sound quality” have been going on for twenty years and they’re all pointless.

Both codecs are lossless. Take a WAV file, encode it to FLAC, decode it back to WAV. Compare it to the original byte-by-byte. They’re identical. Do the same with ALAC. Also identical. The decoded output from FLAC and ALAC is bit-for-bit the same PCM data.

If someone tells you FLAC sounds “warmer” or ALAC sounds “more detailed,” they’re hearing placebo effects. The math doesn’t lie. Lossless means lossless.

File Size Comparison

Both codecs compress audio to roughly the same size. FLAC tends to be slightly smaller, typically by 1-3%, because its compression algorithm is a bit more efficient. The difference is negligible in practice.

Track (4 min)	FLAC	ALAC	MP3 320k
Pop song	~28 MB	~29 MB	~9 MB
Classical	~35 MB	~36 MB	~9 MB
Jazz	~30 MB	~31 MB	~9 MB

For a 500-album library, the difference between all-FLAC and all-ALAC might be 2-4 GB total. Not enough to care about.

Compression Speed

FLAC offers compression levels from 0 (fastest, largest files) to 8 (slowest, smallest files). The default is level 5, which is a good balance. ALAC doesn’t expose compression levels — it uses a fixed algorithm.

Decoding speed is essentially instant for both on any modern hardware. Your iPhone’s processor decodes lossless audio without breaking a sweat. Battery impact is identical.

Metadata and Tagging

Both formats support full metadata: track title, artist, album, year, genre, track number, album art, lyrics, replay gain — all of it. FLAC uses Vorbis Comments, ALAC uses Apple’s MP4/M4A container with iTunes-style tags.

Every decent tagging tool (MusicBrainz Picard, Mp3tag, Kid3) handles both formats. You won’t have metadata issues with either one.

Ecosystem and Compatibility

This is where the actual difference lives.

ALAC works natively on: iPhone, iPad, Mac, Apple TV, HomePod, AirPods, Apple Music app, iTunes, Logic Pro, GarageBand. Basically the entire Apple ecosystem, no third-party apps needed.

FLAC works natively on: Android phones, Windows (via Windows Media Player, Groove, or any player), Linux, most portable DAPs (FiiO, Sony Walkman, Astell&Kern), car head units, smart speakers, Sonos, basically everything except Apple’s built-in apps.

FLAC on Apple devices: The iOS Files app can play FLAC files one at a time, but there’s no library management. Safari can play FLAC in a web page. But Apple Music, iTunes, and the built-in Music app don’t support FLAC at all. You need a third-party player.

This is the core trade-off. If you only use Apple devices, ALAC is the path of least resistance. If you use a mix of Apple and non-Apple devices, FLAC is more universal. If you use a third-party player like LudyAmp on your iPhone, it plays both natively, so the format choice doesn’t matter at all.

Should You Convert?

Probably not. Converting between FLAC and ALAC is lossless in both directions — no quality loss either way. But it’s also unnecessary work if your player handles both.

The only scenarios where conversion makes sense:

You want to use Apple Music app on iPhone as your sole player, and your library is all FLAC. Convert to ALAC so it imports cleanly into iTunes/Music.

You’re sharing files with someone on Android or a portable DAP, and your library is all ALAC. Convert to FLAC for broader compatibility.

If you do convert, use XLD (Mac), fre:ac (cross-platform), or dbPoweramp (Windows). All three handle batch conversion well and preserve metadata.

My Recommendation

Keep whatever format you already have. Don’t convert for the sake of converting. If you’re starting a new library from scratch, FLAC is the safer long-term bet because it’s supported by more devices and software. But if you’re deep in the Apple ecosystem and never touch anything else, ALAC is perfectly fine.

If you’re curious about how either format compares to lossy codecs, I covered that in FLAC vs MP3: Can You Actually Hear the Difference?. And if you need help getting FLAC files working on your iPhone right now, How to Play FLAC Files on iPhone has everything you need.