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AIFF to MP3 converter

Convert AIFF audio to MP3 with configurable bitrate and metadata options.

Free & unlimited
All processing happens in your browser — files never leave your device. The audio engine loads once from a CDN.

AIFF is Apple's uncompressed PCM format, the Mac equivalent of WAV, and it is what Logic, GarageBand and older Mac recorders bounce by default. Like WAV it is enormous — roughly 10 MB per stereo minute at CD rate — and it is not what you put on a phone or send to a podcast host. This converter encodes AIFF to MP3 with libmp3lame in your browser. Because AIFF is uncompressed, the encoder is working from a full-quality master, so this is a single lossy generation and 320 kbps genuinely gets close to transparent. Four bitrate presets, an optional VBR mode, and ID3 metadata including artwork preserved by default.

Key facts about AIFF to MP3 converter

Key facts about AIFF to MP3 converter
AIFF is uncompressed PCMApple's counterpart to WAV, with big-endian sample ordering; both store audio with no compression at all
First-generation encodeThe source is lossless, so the MP3 encoder works from the full signal — the best case for MP3 quality
Bitrate presets320 maximum, 256 high, 192 balanced, 128 compact; default is 320 because the source justifies it
VBR optionlibmp3lame quality level 2, averaging around 190 kbps with bits allocated by complexity
Typical size dropA 50 MB AIFF becomes about 11 MB at 320 kbps or 7 MB at 192 kbps — roughly a five to seven times reduction
MetadataID3 fields including title, artist, album and artwork are preserved by default
Sample rate limitMP3 tops out at 48 kHz, so a 96 kHz AIFF is resampled during conversion
Bit depthA 24-bit AIFF's extra depth has no MP3 equivalent; the format has no bit-depth concept
BatchConvert several files at once and download them as a ZIP built in the browser
Size cap200 MB per file, which is about twenty minutes of 16-bit stereo AIFF

What happens to your file

The encode runs on ffmpeg compiled to WebAssembly inside a Web Worker in this tab. Your AIFF files go into that worker's in-memory filesystem, the MP3s come back as blobs, and the batch ZIP is built in the browser. Nothing is uploaded and no copy is stored. One network request happens: the first time you use an audio tool here the browser fetches the ffmpeg core, about 32 MB of fixed public code from the jsDelivr CDN, which it then caches and reuses. That download contains no part of your files.

About this tool

  1. 1

    Add the AIFF files

    Drop .aiff or .aif files, up to 200 MB each — around twenty minutes of 16-bit stereo, less for 24-bit or high-resolution bounces.

  2. 2

    Choose a bitrate

    320 kbps is the default and appropriate from an uncompressed source. 192 kbps halves the size again and is still excellent for casual listening.

  3. 3

    Consider VBR

    Variable bitrate is slightly smaller at comparable quality. Turn it off if the destination is old hardware that handles VBR MP3 badly.

  4. 4

    Keep metadata

    Preservation is on by default, carrying title, artist, album and artwork into the MP3's ID3 tags — useful for Logic bounces that were already labelled.

  5. 5

    Convert

    Files process one at a time with per-file progress and a summary line showing the exact settings applied.

  6. 6

    Download

    Individually or as a ZIP. Keep the AIFF masters; they are what you re-encode from next time.

Specs & compatibility
InputAIFF and AIF (.aiff, .aif, audio/aiff, audio/x-aiff), up to 200 MB per file
OutputMP3 via libmp3lame, constant or variable bitrate
Bitrates128, 192, 256, 320 kbps
MetadataID3 tags and embedded artwork preserved when the toggle is on
Sample rateMatched to the source, subject to MP3's 48 kHz ceiling
Batch outputIndividual downloads or a single client-side ZIP
EngineSingle-threaded ffmpeg.wasm 0.12.10, ~32 MB core cached after first use
BrowsersChrome, Edge, Firefox and Safari 15+
  • Keep the AIFFs. They are the uncompressed master, and every future conversion should start from them rather than from an MP3.
  • 320 kbps or VBR is worth it here in a way it is not when converting one lossy format to another — the encoder has the full signal to work with.
  • A 24-bit AIFF has no direct MP3 equivalent, because MP3 has no bit-depth concept. Nothing goes wrong; the extra depth simply has nowhere to live.
  • A 96 kHz AIFF is resampled to 48 kHz or lower, since that is MP3's ceiling. If the high sample rate matters, use FLAC instead via the general audio converter.
  • For archiving rather than distribution, converting AIFF to FLAC keeps the audio lossless at roughly half the size.
  • The 200 MB cap bites fast on uncompressed audio — a single long AIFF can exceed it. Split it with the audio trimmer first if needed.
  • If the bounce is quiet, normalize before converting so the MP3 encoder works at a sensible level rather than on a quiet signal.
  • Four bitrate presets from 128 to 320 kbps
  • Optional MP3 variable bitrate
  • ID3 metadata and artwork preservation
  • Accepts both .aiff and .aif extensions
  • Batch conversion with per-file progress
  • ZIP download for whole sessions
  • In-page playback of the result
  • Making MP3 reference mixes from Logic or GarageBand AIFF bounces
  • Shrinking a folder of AIFF masters into something you can email
  • Preparing MP3 versions of recordings for a podcast host that requires them
  • Converting old Mac audio files for a phone or a car stereo
  • Producing listening copies of session bounces while keeping the AIFF masters
  • Getting AIFF field recordings into a format that plays on any device
AIFF is Apple's uncompressed audio format and WAV is Microsoft's; both store raw PCM samples with no compression, and both are about 10 MB per stereo minute at CD rate. The main technical difference is byte order — AIFF stores samples big-endian, WAV little-endian — which matters to software and not at all to listeners. In practice AIFF is what Mac audio applications bounce by default and WAV is what Windows ones produce. Neither is better; converting either to MP3 works identically.
As good as MP3 gets, because you are encoding from an uncompressed master. This is a first-generation lossy encode: the encoder has the complete original signal and makes its own decisions cleanly, rather than trying to re-encode something another codec already damaged. At 320 kbps or with VBR, most listeners cannot distinguish the result from the AIFF in normal conditions. Where a difference shows up is on dense high-frequency material through good headphones in a quiet room.
Around five to seven times smaller, depending on bitrate. A 50 MB AIFF typically becomes about 11 MB at 320 kbps, 9 MB at 256, or 7 MB at 192. The saving is large because AIFF stores every sample at full precision with no compression whatsoever, while MP3 discards everything its psychoacoustic model judges inaudible. If you want a smaller file without any loss, convert to FLAC instead — that gets you roughly half the AIFF's size with identical audio.
Both are reduced, because MP3 cannot represent either. MP3 has no concept of bit depth at all, so a 24-bit source simply passes through the normal encoding path — nothing breaks, the extra precision just has nowhere to go. Sample rate is a firmer limit: MP3 supports up to 48 kHz, so an 88.2 or 96 kHz AIFF is resampled during conversion. If those properties matter to you, keep the AIFF or convert to FLAC, which preserves both.
Yes, when metadata preservation is on, which is the default. Title, artist, album and embedded artwork are written into the MP3's ID3 tags. This matters for bounces out of a DAW that were already labelled, and for AIFF files ripped from CDs by older Mac software. Switching preservation off strips the metadata entirely, which is occasionally what you want when sharing a file and you would rather not include session names or identifying information.
No. The encode is performed by ffmpeg compiled to WebAssembly, running in a Web Worker on your own device. Your AIFF goes into that worker's in-memory filesystem and the MP3 comes back as a blob in your tab; the batch ZIP is built in the browser too. The only network request is the one-time fetch of the ffmpeg core — about 32 MB of fixed public code from the jsDelivr CDN, identical for every visitor and cached after the first use.

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