What Is an AIFF File? Format, Quality, and Uses

What is an AIFF file?

An AIFF file is audio saved in the Audio Interchange File Format, a container Apple introduced in 1988. In its standard form it holds uncompressed PCM audio. The samples are stored exactly as they were recorded or exported, without the data loss of formats such as MP3 or AAC. AIFF files usually end in .aiff or .aif. They play natively on macOS and open in most professional audio software.

In practice, AIFF is the Mac counterpart to WAV. Both store the same kind of uncompressed audio, and at the same bit depth and sample rate they sound identical. The trade-offs are large files and less consistent support outside Apple software and professional tools.

How the AIFF format works

AIFF is based on the Interchange File Format (IFF), which Electronic Arts created. An AIFF file is organized into chunks:

• FORM: the outer chunk that identifies the file as AIFF and contains everything else.
• COMM (Common chunk): describes the audio, including the number of channels, number of sample frames, sample size (bit depth) and sample rate.
• SSND (Sound Data chunk): holds the audio samples themselves.
• Optional chunks: can store markers, instrument data such as sampler loop points, comments and other metadata.

An AIFF file has no single fixed quality. A player reads the values in the Common chunk to play the audio correctly, so the quality reflects whatever settings were used when the file was created. CD audio is 16-bit, 44.1 kHz stereo. Recording and video projects often use 24-bit at 48 kHz or higher.

Standard AIFF stores samples in big-endian byte order, a legacy of the Motorola-based Macs it was designed for. WAV uses little-endian order. This does not change the sound. It does explain why the two formats are not interchangeable at the file level even when the audio inside is the same.

A variant called AIFF-C (often with the .aifc extension) adds a field that names the compression type. It can hold compressed audio, and it can also hold uncompressed audio in little-endian order. A file with an .aif extension may be AIFF-C internally. If a program rejects an .aif file, check which variant it actually is.

Because the audio is uncompressed, file size depends only on the settings and the duration: sample rate × bytes per sample × channels. For 16-bit, 44.1 kHz stereo that is 176,400 bytes per second, about 10.6 MB per minute. For 24-bit, 48 kHz stereo it is 288,000 bytes per second, about 17.3 MB per minute.

When to use AIFF audio files

• Recording and editing: when you capture audio from a microphone or audio interface, saving as AIFF keeps every sample for editing. Repeated lossy encoding, by contrast, loses a little more quality each generation.
• Mac-based workflows: Apple apps and audio workstations on macOS handle AIFF natively, so it is a common choice for masters and stems.
• Samples and loops: the marker and instrument chunks can carry loop points that some samplers read.
• CD archiving: AIFF preserves CD audio bit for bit, although lossless compressed formats do the same in less space.
• Sharing: if the recipient uses Windows, a web browser or a phone, WAV or a compressed format may be the safer choice. Check what their software supports.

The format cannot improve a recording beyond what the input device captured. Set the input level so peaks do not clip. Choose the sample rate your project uses so the audio is not resampled later; video work commonly uses 48 kHz. Reduce background noise at the source. AIFF stores noise and distortion as faithfully as the voice.

AIFF compared with other audio formats

• AIFF vs WAV: the same uncompressed quality at the same settings. Choose based on compatibility: AIFF fits Apple-centric tools, while WAV is more common on Windows and in broadcast and video tools.
• AIFF vs FLAC or ALAC: these are lossless compressed formats. They decode to the same audio while using less storage, and they generally handle tags better.
• AIFF vs MP3 or AAC: these lossy formats discard data to make files much smaller. They suit listening and streaming, not editing masters.

When converting, keep the original AIFF file. Conversion to a lossy format cannot be reversed. Online converters upload your file to another party's server, so check the service's privacy and retention terms before uploading private material such as interviews or meeting recordings. Desktop audio software can often convert files locally without uploading them.

Limits and related questions

• File size limit: chunk sizes are stored as 32-bit values, so a single AIFF file is limited to about 4 GB. Long multichannel recordings at high sample rates can reach this limit. Formats such as Apple's Core Audio Format (CAF) or RF64 are designed for larger files.
• Playback support: support in web browsers, phones and non-Apple players varies by app and version. Verify playback on your audience's platforms before using AIFF for distribution or web embedding.
• Metadata: AIFF can carry tags, often in an ID3 chunk, but apps handle them less consistently than MP3, M4A or FLAC tags. Titles or artwork may not appear in every player.
• Output device: the operating system may resample audio to match the output device's current sample rate. This is controlled by system and device settings, not by the file.

Is AIFF lossless? Standard AIFF is uncompressed, so no audio data is lost. An AIFF-C file may use compression, and whether it is lossless depends on the codec named inside the file.

Is AIFF better than WAV? Neither sounds better at identical settings. The practical difference is which software and platforms open each format most reliably.

Does AIFF matter for video calls? Calling apps send live audio in their own compressed formats. AIFF only matters if you save, edit or export a recording afterward, and only if your software offers it as an option.