From uncompressed AIFF to compact MP3
AIFF is Apple's uncompressed audio format, introduced in 1988 and based on Electronic Arts' IFF container. It stores PCM samples in big-endian order, usually at 16 or 24-bit and 44.1 or 48 kHz. It is common in Logic and GarageBand bounces, CD rips made in older versions of iTunes, and sample libraries.
MP3 is the lossy MPEG-1 Audio Layer III format from 1993. It uses a psychoacoustic model to discard sounds you are unlikely to hear, which cuts file size dramatically. AudioDrop encodes it with a LAME-based encoder.
AIFF vs MP3 in numbers
A 16-bit/44.1 kHz stereo AIFF is about 10.1 MB per minute. Here is what MP3 does to that:
| AIFF | MP3 320 kbps | MP3 192 kbps | MP3 128 kbps | |
|---|---|---|---|---|
| Compression | None | Lossy | Lossy | Lossy |
| Size per minute | ≈ 10.1 MB | ≈ 2.4 MB | ≈ 1.44 MB | ≈ 0.96 MB |
| 4-minute song | ≈ 40 MB | ≈ 9.6 MB | ≈ 5.8 MB | ≈ 3.8 MB |
| Reduction | Baseline | About 77% | About 86% | About 90% |
| Quality | Exact PCM | Very hard to tell apart | Transparent for most listeners | Fine for speech, audible on some music |
| Best for | Editing, masters | Critical listening, DJs | General listening | Voice, podcasts, previews |
Why convert AIFF to MP3
Size and reach. A folder of AIFF files fills a phone quickly and is awkward to email or share. MP3 is a tenth of the size at low bitrates and plays on Windows, Android, car stereos, web players and nearly every app. AIFF, by comparison, is well supported on Apple devices and less so elsewhere.
Typical uses: sending a mix to a client for feedback, putting an album on a phone or USB stick, uploading a demo to a site that caps file size, or sharing a voice recording from a Mac.
Quality: what you keep and what you lose
AIFF to MP3 is lossless to lossy. Some information is removed, and it cannot be put back later. Your bitrate decides how much. At 320 kbps most people cannot tell MP3 from the original in blind listening. At 192 kbps it is still clean for general listening. At 128 kbps speech is fine but cymbals and reverb tails can start to sound smeared.
Keep the AIFF as your master. If you need an MP3 at a different bitrate later, encode it again from the AIFF, not from an existing MP3. That avoids stacking generations of loss.
Recommended settings
- Finished music you care about: 320 kbps.
- Albums for your phone or car: 192 or 256 kbps.
- Podcasts, lectures and voice memos: 128 kbps.
- 24-bit AIFF sources encode straight to MP3, so bit depth does not matter here.
- Tags in the AIFF may not all transfer, so check title and artist afterwards.
Convert AIFF to MP3 on Mac, Windows or your phone
On a Mac, open AudioDrop in Safari or Chrome and drag the AIFF files straight from Finder or a Logic bounce folder. On Windows, use Chrome, Edge or Firefox. You do not need iTunes or Music to do the conversion. On iPhone, Safari can pick AIFF files from the Files app, and Android Chrome can open them from Downloads.
Converting a full album is a good use of batch mode. Drop all the tracks together, set the bitrate once, and the files encode in parallel. You then save each MP3 as its download appears. Because MP3 files are so much smaller, the whole album will usually fit on a phone or in an email where the AIFF set would not.
Browser-based and private
AudioDrop is an AIFF to MP3 converter that never uploads your files. The AIFF is read on your device, and the MP3 is encoded in WebAssembly inside your browser. Unreleased tracks and client mixes stay with you.
It is free with no account or watermark. It works offline once the page has loaded, has no fixed file size limit beyond your device's memory, and converts batches several files at a time, each downloading separately.