AIFF to MP3 Converter

AIFF is Apple's uncompressed audio format, used by Logic, GarageBand, Pro Tools and CD rips on a Mac. The files are large and many phones, web forms and players do not accept them. This converter reads AIFF and AIFC files itself, in your browser, and encodes them as MP3 with LAME, keeping the title and artist. Nothing is uploaded and no extra download is needed for ordinary AIFF files.

How to use this tool

1. Choose one or more .aif, .aiff or .aifc files.
2. Pick the MP3 bitrate: 256 or 320 kbps for music masters, 128 kbps for speech.
3. Keep the sample rate (96 and 88.2 kHz files become 48 or 44.1 kHz, the highest MP3 rates).
4. Press Calculate and download the MP3 files.

Formula

MP3 size ≈ bitrate (kbps) × 1000 ÷ 8 × length (s) · AIFF size = sample rate × channels × bytes per sample × seconds

The tool reads the AIFF chunks itself: COMM for the channels, length, bit depth and the 80-bit sample rate, SSND for the big-endian samples, plus AIFC "sowt" (little-endian), 32- and 64-bit float and µ-law / A-law, and the ID3, NAME and AUTH chunks for tags. Compressed AIFC (IMA ADPCM, MACE) and very long files go to the ffmpeg engine (about 30 MB, downloaded once). Masters that peak near 0 dBFS are checked after encoding and lowered just enough if the MP3 would clip.

Example

A 4-minute stereo AIFF from a CD (16-bit, 44.1 kHz) is 44,100 × 2 × 2 × 240 ≈ 42.3 MB. As an MP3 at 256 kbps it becomes 256,000 ÷ 8 × 240 = 7.68 MB, about 82% smaller.