AIFF vs FLAC: Which Lossless Format Should You Use?
AIFF vs FLAC: both are lossless and sound the same. Compare file size, Apple support, tags and editing, and see which to use for your library or studio.
The quick answer
Neither sounds better: AIFF and FLAC are both lossless, so the same recording decodes to the same samples. FLAC packs it into roughly half to two-thirds of the space and is open and widely supported. AIFF is uncompressed and plays in Apple's Music app, which does not import FLAC. Choose FLAC to store music, AIFF for Apple-app and editing workflows.
- Same sound — both keep every bit; FLAC just compresses it without loss.
- Size — a 4-minute CD-quality song is 42.3 MB as AIFF and about 21–30 MB as FLAC.
- Apple — the Music app adds AIFF, not FLAC. For a smaller Apple-friendly file, use Apple Lossless.
- Need FLAC from AIFF? Convert AIFF to FLAC in your browser — nothing is uploaded.
Do it in your browser — free, no upload
AIFF and FLAC are both lossless audio formats, so neither throws any sound away. They take different routes to get there: AIFF stores the audio uncompressed, while FLAC compresses it the way a ZIP file compresses text, then rebuilds it exactly on playback. This guide compares them on sound, size, device support, tags and editing, and ends with a clear rule for which to use.
The short answer
- Sound: identical. The same recording decodes to the same samples in both.
- Size: FLAC is usually 50 to 70% of the AIFF size.
- Apple: the Music app and iTunes add AIFF files to a library but not FLAC.
- Everywhere else: FLAC is open and plays on most modern systems; AIFF is most at home on a Mac.
- Rule of thumb: store and listen in FLAC; use AIFF (or Apple Lossless) inside Apple's apps.
How each format works
AIFF (Audio Interchange File Format) was developed by Apple in 1988. Standard AIFF holds PCM audio: a plain list of measurements of the sound wave, stored exactly as recorded, with no compression. That makes it simple to read and edit, and large.
FLAC (Free Lossless Audio Codec) takes the same samples and packs them into less space. It predicts each sample from the ones before it and stores only the small error in that prediction. When you play the file, the decoder rebuilds every sample exactly. FLAC was published as an internet standard, RFC 9639, in December 2024, and every file stores a checksum of the original audio so software can confirm it is intact.
Do they sound different?
No. Lossless means the decoded audio matches the source sample for sample. A 16-bit, 44.1 kHz FLAC made from an AIFF plays back the very same samples as that AIFF. If you hear a difference in a comparison, something else changed: the volume, the bit depth, the sample rate, or a setting in the player.
File size compared
| Content (stereo) | AIFF | FLAC (typical 50–70%) |
|---|---|---|
| 1 minute, 16-bit / 44.1 kHz | 10.6 MB | 5.3 to 7.4 MB |
| 4-minute song, 16-bit / 44.1 kHz | 42.3 MB | 21 to 30 MB |
| 4-minute song, 24-bit / 96 kHz | 138 MB | 69 to 97 MB |
| 1,000 CD-quality songs | 42 GB | 21 to 30 GB |
How much FLAC saves depends on the music. Quiet, simple recordings shrink the most; loud, dense masters shrink the least. FLAC's compression level (0 to 8) only trades encoding time for size. Every level decodes to the same audio.
Device and app support
- Apple's Music app and iTunes add AIFF files to a library but not FLAC. If you want a smaller lossless file there, use Apple Lossless (ALAC); see FLAC vs ALAC.
- Mac: macOS plays both. FLAC support arrived in macOS 10.13 High Sierra.
- Windows: has played FLAC natively since Windows 10; AIFF is less common there.
- iPhone and iPad: iOS 11 and later can play FLAC files, for example from the Files app, but not inside the Music app.
- Android: has supported FLAC since Android 3.1.
- Audio editors: most open both. Some samplers and older tools want uncompressed files such as AIFF or WAV.
Tags and cover art
Both formats can carry tags such as title, artist and album, and both can hold cover art. FLAC stores tags as Vorbis comments with embedded pictures. AIFF has text chunks for name, author, comments and copyright, and it can also embed an ID3v2 tag block, the system MP3 uses. Programs do not always read every option the same way, so if tags matter for your library or DJ software, tag one file of each type and check that it shows up correctly in the software you use.
Editing and recording
For recording and editing, uncompressed files are the usual working format, because there is no decoding step and every tool accepts them. That favours AIFF (or WAV) during a project. FLAC is a great way to store the finished result: the same audio in less space, with a built-in check that it has not been damaged. A common workflow is to record and edit in AIFF or WAV, then archive the masters as FLAC.
Hi-res files: 24-bit and beyond
Both formats can hold more than CD quality. Hi-res downloads often come as 24-bit files at 96 kHz, which take about 3.3 times the space of the same music at CD quality. That is where FLAC's compression matters most: a hi-res album that would fill well over a gigabyte as AIFF shrinks considerably as FLAC, with every sample kept.
Whether you can hear the extra resolution is a separate question. A 2016 review of 20 listening tests in the Journal of the Audio Engineering Society found a small but measurable ability to tell hi-res from CD-quality audio, much stronger in trained listeners; other researchers note the overall result was only a little better than guessing. Either way, if you buy hi-res files, FLAC is the space-efficient way to keep them.
How to check a file before you rely on it
- MediaInfo, a free app for Windows, Mac and Linux, shows the format, bit depth and sample rate of any audio file, so you can confirm what you actually have.
- FLAC's checksum lets you test a file years later. The official flac command-line tool has a test mode (flac -t) that decodes the file and compares the result with the stored checksum, so damage from a failing drive shows up as an error. AIFF has no built-in checksum, so a damaged AIFF may simply play with a click or a gap.
Common myths
- "FLAC is compressed, so it must sound worse." Its compression is lossless, like a ZIP file: nothing is thrown away.
- "AIFF is the audiophile choice." AIFF and FLAC hold the same samples. Preference usually comes down to software, not sound.
- "Higher FLAC compression levels lower the quality." They only change file size and encoding time.
- "Converting back and forth wears out the file." Not when the bit depth and sample rate stay the same.
Which should you choose?
| Situation | Choose |
|---|---|
| Music library on a computer, phone or media server | FLAC |
| Apple Music or iTunes library | AIFF, or Apple Lossless to save space |
| Recording and editing on a Mac | AIFF (or WAV) |
| Long-term archive of masters | FLAC |
| Sending files to someone on an unknown system | FLAC for listening, WAV for editing |
| Hi-res downloads | FLAC (keeps 24-bit and high sample rates in less space) |
Converting between AIFF and FLAC
Converting either way is lossless when the bit depth and sample rate stay the same, so you can move between them as often as you need. Our AIFF to FLAC converter runs in your browser with FFmpeg and never uploads your files. For the reverse, convert FLAC to WAV (WAV and AIFF hold the same uncompressed audio) or FLAC to Apple Lossless for Apple's apps. Free users get 5 conversions per month. The output is limited to the first 10 seconds as a preview, with a 20MB input file size limit. Upgrade to Pro for unlimited, full-length conversions.
The bottom line
AIFF and FLAC hold the same sound. FLAC is the better way to store and carry music: smaller, open, widely supported and self-checking. AIFF is the better fit inside Apple's Music app and during editing, where uncompressed files are simplest. Many people use both: AIFF or WAV while they work, FLAC for the finished library.