How AIFF Works
AIFF (Audio Interchange File Format) is Apple's uncompressed audio format, and the simplest way to understand it is as the Apple equivalent of WAV. Both store raw, lossless PCM audio inside a chunk-based container; they differ mainly in their origins and a small technical detail of how the bytes are ordered. AIFF was derived from Electronic Arts' Interchange File Format (IFF), which organizes a file into typed "chunks", each labeled with a four-character code and a length.
A standard AIFF holds two key chunks. The COMM chunk describes the format: sample rate, bit depth, and channel count. The SSND chunk holds the sound data itself, stored as uncompressed linear PCM. That uncompressed storage is the whole point of AIFF, every sample is preserved exactly as recorded, with no quality loss and no decoding step, which is why it is favored for editing and mastering.
The one technical quirk worth knowing is byte order. AIFF stores its samples in big-endian order, the native ordering of the Motorola 68000 processors used in the early Macintosh computers AIFF was designed for. WAV, born on Intel-based PCs, uses little-endian order. The difference is invisible to you in practice because modern software reads both, but it is the reason the two formats exist separately for what is otherwise the same kind of audio. The Library of Congress recognizes a strict LPCM-only subtype of AIFF as a preferred format for long-term audio preservation.
AIFF-C and Compression Variants
A later revision called AIFF-C (sometimes written AIFC) extended the format to allow compressed audio codecs inside the same container, rather than only raw PCM. In principle this lets an AIFF-C file hold compressed audio, but in everyday use the overwhelming majority of AIFF files you encounter are plain uncompressed PCM. When people say "AIFF" they almost always mean the lossless, uncompressed kind, and AIFF-C compression is rarely seen in practice.
AIFF can also carry metadata chunks for things like track names and annotations, though its metadata support is less rich and less standardized than modern formats like FLAC. For this reason AIFF is treated as a working and mastering format rather than a library format for tagged music collections.
AIFF vs WAV: Which Should You Use?
Because AIFF and WAV are functionally equivalent (both uncompressed, lossless PCM), the choice usually comes down to your ecosystem. AIFF is the natural fit in Apple-centric workflows: it is the default uncompressed format in Logic Pro and integrates cleanly with macOS and iOS tools. WAV is the cross-platform default and the more universal choice when files move between Windows, Mac, and a wide range of audio software.
In terms of sound and file size there is no difference, a minute of CD-quality stereo is roughly 10 MB in either format, and neither loses any quality. If you work primarily in Apple software, AIFF is convenient; if you need the broadest compatibility, WAV is safer. For distribution rather than editing, you would convert either one to a smaller format like MP3, AAC, or FLAC.
Limitations
AIFF shares WAV's core drawback: with no compression, files are large, roughly ten times the size of an equivalent MP3, which makes AIFF impractical for streaming, email, or storing big music libraries. Like classic WAV, traditional AIFF also carries a file-size ceiling near 4 GB because of 32-bit size fields, which can matter for very long high-resolution recordings. And because it originated in the Apple world, AIFF historically had weaker support on non-Apple platforms, though modern software on every system now reads it without trouble.
