Upload a AIFF file and get a M4A back. No signup, no watermark, no limit on how many.
AIFF is Apple's uncompressed PCM format — WAV's opposite number, same audio, different byte order and a container that handles tags rather better.
Where you run into it: Logic and Pro Tools sessions, Mac recordings, older Apple software that wrote it by default.
What it costs you: As big as WAV, and outside the Mac world rather less widely accepted.
M4A is an MPEG-4 container holding AAC audio — the same codec as a bare .aac file, wrapped so that players, tags and cover art all behave.
Where you run into it: iTunes and Apple Music purchases, voice memos, Zoom and Teams recordings, most phone-recorded audio.
What it costs you: Outside Apple's ecosystem support is good but not universal, and a few older tools still refuse the extension on sight.
This is the conversion that actually buys you something: AIFF holds the full signal, and M4A trades a slice of it for a file a fraction of the size. This is where the bitrate setting matters — 320 kbps for music you care about, 192 for general listening, 128 for speech. It is a one-way trip, so keep the AIFF original if it is the only copy you have.
Yes, entirely, and there is no cap on how many files you convert. No account, no watermark, no trial.
Yes — that is the point of it. M4A discards part of the signal to get small. At the best setting the difference is inaudible to almost everyone on almost any equipment; at 128 kbps it is audible on music and fine on speech.
Much smaller — commonly a tenth of the AIFF at 320 kbps, and less again at lower settings. That reduction is exactly what you are trading a slice of the signal for.
Not here. AIFF can be read but not written by this converter — ffmpeg decodes it happily, and encoding back to it would mean a format almost nothing plays. If you need the original AIFF, keep it rather than recreating it.
The file is uploaded to do the conversion — nothing here runs in your browser — and both your upload and the converted result are deleted the moment the file is sent back. Nothing is stored and nothing is logged beyond the request itself.