What is an AIFF file?

AIFF is a container: a wrapper that holds streams encoded by something else. It is used for editing and archiving.

The extension is .aiff, and the full name is Audio Interchange File Format. Both matter less than what the file can hold, which is what the rest of this page is about.

Apple published it in 1988.

A format that has been readable for that long is a format worth trusting with something you want back in ten years.

It is written down and implementable, though the vendor decides what the next version looks like. In practice that is enough for the file to keep opening; it is not enough to be sure of it.

AIFF stores its content exactly. Saving it again changes nothing, so it can be opened, edited and re-saved as often as you like without accumulating damage — which is what makes it a working format rather than a delivery one.

Up to 32 bits per channel.

More than eight bits per channel is what stops a gradient from stepping when it is edited, which is why it matters in a working file and rarely in a finished one.

It usually holds PCM. This is the distinction behind most "why will this not play" questions: two files with the same extension can contain entirely different encodings, and a player that refuses one may be perfectly happy with the other.

It also explains why changing container is often fast and lossless while changing codec is neither. Moving the same stream into a different box rewrites the box; re-encoding rewrites the picture.

Up to 8. Two covers stereo and is what almost everything is; more than two is surround, and it is the part most likely to be folded down when converting to a format that does not define it.

Logic Pro, Audacity and Adobe Audition read it, and so do most programs of the same kind.

If a file will not open, the format is rarely the problem — it is more often that the program predates it. Converting to something older is the reliable way past that, and it is what the rest of this site is for.

Only some browsers read it.

Where support is uneven, serving a second format alongside it is the usual answer — the browser takes the one it understands and nobody is left out.

AIFF can hold document properties.

Whether any of it survives a conversion depends entirely on the target, and the honest answer is usually "some of it".

AIFF is meant to be opened and changed. Keep the file in this format for as long as the work is going on, and export from it whenever a finished copy is needed.

The recurring complaints: the files are large for what they contain.

None of these is a reason to avoid the format. They are the things worth knowing before you are surprised by one, which is a different claim and a more useful one.

AIFF was published by Apple in 1988; Microsoft and IBM specified WAV three years later, in the August 1991 Multimedia Programming Interface and Data Specifications. Both solve the same problem: store uncompressed audio samples with a header describing how to interpret them. The sizes are identical — about 10 MB per minute at CD quality — because there is nothing to compress away in either.

Apple derived it from Electronic Arts’ Interchange File Format, which the Amiga used. WAV came from RIFF, which is the same idea with the byte order reversed. Two platforms, the same problem, three years apart, and a difference that has caused low-grade friction ever since.

AIFF stores multi-byte values big-endian — most significant byte first, the convention of the Motorola processors Macs used at the time. WAV stores them little-endian, matching Intel. Reading one as the other produces noise rather than a graceful failure.

This is why the two formats exist separately despite being conceptually identical, and why a piece of software may handle one perfectly and refuse the other. It is not a meaningful difference in the audio; it is a difference in how the same numbers are written down, and it long outlived the hardware that motivated it.

This is the difference that actually matters day to day. AIFF was designed with named chunks for a title, author, copyright and annotations, and Apple later allowed ID3 tags inside one. A tagged AIFF library shows track names, artists and cover art properly.

WAV has no meaningful tagging convention — some tools write a small INFO chunk, most write nothing, and support for reading it is inconsistent. That is why Apple built lossless ripping in iTunes around AIFF rather than WAV, and why a WAV library arrives as a folder of file names while an AIFF library arrives organised.

Older iTunes libraries, where AIFF was the uncompressed ripping option for years. Logic Pro and GarageBand exports. Professional audio work on Macs, where AIFF and WAV are used interchangeably and the choice is often just what the engineer set once. Sample libraries and sound effect collections. And older Mac software generally.

The pattern is Apple’s ecosystem rather than any technical requirement. Nobody chooses AIFF over WAV for a property of the format in 2026; they have it because a Mac produced it.

AIFF-C, sometimes written AIFC, extends the format to allow compressed audio inside the same container. It can hold IMA ADPCM, µ-law, and on Apple systems even other codecs.

So a file with a `.aiff` or `.aif` extension is not guaranteed to be uncompressed. This is rare and it is the usual explanation when an AIFF is far smaller than the arithmetic says it should be, or when it refuses to open in something that handles other AIFFs without difficulty.

The IFF chunk header AIFF inherits declares its size in a signed 32-bit field, where RIFF uses an unsigned one. So the ceiling is 2,147,483,647 bytes rather than WAV’s 4 GB — about 3 hours 23 minutes at CD quality, and 1 hour 02 minutes at 24-bit and 96 kHz.

WAV has extensions that lift the limit, RF64 and BWF, which professional recorders write for long-form work. AIFF has no equivalent in common use. For a long recording session that makes WAV the more practical of the two uncompressed formats, which is a rare case where the choice between them is not arbitrary.

Every conversion listed on this page writes an AIFF. There is no AIFF-to-anything page, because the demuxer this site runs does not parse the container — the samples inside are ordinary PCM and nothing else is in the way, which is why the gap is a missing reader rather than a missing decoder. Software that demands a WAV from an AIFF you already hold needs a desktop tool.

What the other direction writes is 16-bit PCM: the file is muxed as a WAV and then rewrapped, since the two containers hold the same samples in opposite byte order. So a 24-bit master converted to AIFF here comes out truncated to 16 bits, and the metadata the source carried is not written into the AIFF chunks that could hold it.

ALAC or FLAC when the audio must stay lossless but the size is impractical. Both give back exactly the same samples at roughly half the size, and both have proper tagging — ALAC if the library lives in Apple Music, FLAC for everything else.

MP3 or AAC when the file needs to move to a phone, a car or an email. Expect about a tenth the size; 128 kbps for speech and 192 or higher for music. Converting to WAV only when a specific program insists, since the file stays the same size and loses its tags.

The conversion happens inside your browser tab, so the audio is never transmitted. Given the size of uncompressed audio that is a practical point before it is a privacy one: an hour of AIFF is around 600 MB, which is beyond what most upload-based converters will accept at all.

The free tier stops at 100 MB per file and 100 files at a time, which for uncompressed audio is about ten minutes a file, so an hour-long session has to be split before it will go through. What there is none of is a queue, an account or a daily allowance. For recorded music, interviews and session archives — which is most of what exists as AIFF — that combination is the one worth having.