Convert AIFF to MP3

Where AIFF files come from

Apple created AIFF in 1988, and Mac audio software still leans on it:

• Bounces and stems from Mac music apps such as Logic Pro and GarageBand.
• Sample packs and sound libraries that ship in AIFF for Mac users.
• CD rips made on a Mac with iTunes set to its AIFF encoder.
• Files from studios and collaborators who work on Macs.

On a Windows PC, most audio editors open AIFF happily, but phones, chat apps, email and upload forms want something far smaller. MP3 is the format that goes everywhere, at a fraction of the size, which is why a Mac-made mix usually needs converting before it can be shared from a PC. The three extensions you'll see, .aif, .aiff and .aifc, belong to the same family, and Octoolo reads them alike.

Bit rate and size

An MP3's size depends only on its bit rate, so it comes out the same whatever the AIFF was. A five-minute 24-bit mix of about 86 MB becomes a 12 MB MP3 at 320 kbps, or 7 MB at 192. The 24-bit samples are encoded directly, and a 96 kHz file is resampled to 48 kHz, the ceiling for MP3.

Mono AIFFs, such as a single vocal or instrument take, get half the stereo rate from each preset: 160 kbps at High, 96 at Balanced, 64 at Small. They stay mono, so a solo take doesn't double in size for nothing.

Sending demos and mixes

For feedback on a mix, Balanced is enough: everyone can play it, and it attaches to an email easily. A whole album's worth of mixes, twelve four-minute songs, comes to about 70 MB at that setting. For a release or a master you care about, hand over the full-quality file instead and keep the MP3 for previews and social posts. Spoken material recorded on a Mac, like a podcast episode or a voice-over, is fine at Small.

Keep your AIFFs as the masters. If you'd like a smaller archive that still loses nothing, pick FLAC in the same window instead of MP3; it keeps 16-bit and 24-bit sound exactly. If a Windows program would rather have WAV, the WAV converter page covers that, and WAV to MP3 describes the same job for files that are already WAV.

Tags, names and stems

AIFF can carry ID3 tags and even a cover picture, and when a file has them, Octoolo copies them into the MP3. Many AIFFs from music apps carry none, though. Because each MP3 takes its AIFF's file name, name the files the way you want the MP3s called before converting: “Band - Song (mix 3).aiff” becomes “Band - Song (mix 3).mp3”.

A folder of stems converts in one go, four files at a time, and each stem keeps its name, so “Drums”, “Bass” and “Vox” still line up when someone drops them into a project. Stereo stays stereo and mono stays mono; a multichannel AIFF is mixed down to two channels, the most an MP3 holds. A mix bounced at 44.1 or 48 kHz keeps that rate in the MP3, so it lines up with any video or project it was made for.