Add your AAC file
Drop one or more .aac files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
AAC to AIFF
Re-encoding .aac audio as .aiff changes how the sound is compressed and which players will accept it. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop AAC files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting AAC audio to Audio Interchange File
Re-encoding .aac audio as .aiff changes how the sound is compressed and which players will accept it. An .aac file holds raw Advanced Audio Coding data, usually as an ADTS stream. AAC was designed as MP3's successor and delivers audibly better quality at the same bitrate, though the bare .aac extension is rarer than AAC audio traveling inside .m4a or .mp4 files.
An .aiff file is Apple's Audio Interchange File Format, storing uncompressed PCM audio much as WAV does on Windows. Mac-based studios have exchanged .aiff masters for decades, and Logic Pro sessions and sample libraries remain full of them. For this route the practical draw is bit-perfect audio identical in fidelity to WAV and loop and marker metadata that samplers actually read — balanced against as bulky as any uncompressed format, which is worth knowing before you commit a large batch.
Why convert AAC to AIFF?
The practical trigger for this conversion is usually a mismatch: with .aac, raw ADTS files handle tags and cover art poorly. Switching to .aiff buys you bit-perfect audio identical in fidelity to WAV, which is why it is the better fit for delivering masters from macOS-based studios. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
AAC vs AIFF at a glance
| Aspect | AAC audio (.aac) | Audio Interchange File (.aiff) |
|---|---|---|
| Format type | Lossy — discards detail it judges invisible to shrink files | Lossless — every pixel or sample is preserved exactly |
| How it stores data | a pure MDCT transform codec, free of the hybrid filterbank compromise that limited MP3 | classic AIFF stores big-endian PCM, the opposite byte order from WAV, in COMM and SSND chunks |
| Strongest at | receiving the audio track copied out of MP4 video without re-encoding | delivering masters from macOS-based studios |
| Weak spot | raw ADTS files handle tags and cover art poorly | as bulky as any uncompressed format |
| Metadata | no standard tag container exists for raw ADTS streams; ID3 tags are sometimes prepended but poorly supported, so wrapping in .m4a is the reliable way to tag AAC | nAME, AUTH, and ANNO chunks provide basic text, marker and instrument chunks store loop data, and an ID3 chunk is a common unofficial extension used by iTunes |
Pick AIFF as the output
Select .aiff in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if AIFF is selectable, the route is real and validated.
Convert on your device
Press Convert. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid AIFF file. Outputs keep the original filename with the .aiff extension.
AAC to AIFF questions, answered
Will converting AAC to AIFF lose quality?
No new loss is introduced — since aac is lossy-oriented and aiff is lossless-oriented, everything the .aac file still contains is carried over exactly. What was already discarded by the original lossy encode cannot be recovered, though; converting to .aiff does not "restore" quality.
Is it private to convert AAC files here?
Yes — the .aac file is processed inside your browser tab and never uploaded. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device. Close the tab and the file is gone from memory.
Where will the AIFF file work?
macOS and all serious audio software open .aiff without hesitation, and Windows editors generally support it even though WAV is their default. Browsers offer partial support at best, and the format's size makes it a poor web choice regardless.
Will the AIFF file be bigger or smaller than my AAC?
Larger, sometimes much larger. A lossless .aiff must store every pixel or sample the decoder produced, without the perceptual shortcuts .aac used. Use this route for editing headroom, not for saving space.
What happens to the metadata in my AAC file?
This converter strips container metadata deliberately (the FFmpeg command runs with metadata mapping disabled) so exported files do not leak recording details. In the source, no standard tag container exists for raw ADTS streams; ID3 tags are sometimes prepended but poorly supported, so wrapping in .m4a is the reliable way to tag AAC; none of it is transmitted anywhere because the file never leaves your browser.
Can I convert AIFF back to AAC?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .aac → .aiff → .aac is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.