Upload a M4A file and get a WAV back. No signup, no watermark, no limit on how many.
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.
WAV is raw, uncompressed PCM in a Microsoft container: the audio exactly as it was sampled, with nothing clever done to it.
Where you run into it: Recording sessions, sample libraries, video editors, anything that has to be edited rather than merely listened to.
What it costs you: It is enormous — roughly 10 MB a minute in CD-quality stereo — and it carries almost no tagging, so a folder of WAVs is a folder of filenames.
What happens depends on what your .m4a actually holds, because the extension names a container and not a codec. Usually it is AAC, which is decoded to PCM and written as a WAV — a faithful copy of a lossy file. Sometimes it is Apple Lossless, and then the audio inside was already intact and the WAV is simply an uncompressed version of it. Either way one detail is worth knowing in advance: WAV is written here at 16 bits, so a 24-bit ALAC file is rounded down on the way out. For AAC that is irrelevant; for a 24-bit master it is not what you want.
The common case here is a recording rather than a song. iPhone Voice Memos, WhatsApp notes and most Android recorders all write AAC inside an .m4a, and the places people want to take them — Audacity, a transcription service, Premiere, a phone system — ask for WAV. Those recordings are mono, so halve every figure above. If instead you arrived with a music library, convert to FLAC rather than WAV: the same fidelity in half the disk, and a file that can later prove it has not corrupted. The cover art survives neither route, since an attached image is dropped, so keep the .m4a if the artwork matters to you.
Yes, entirely, and there is no cap on how many files you convert. No account, no watermark, no trial.
For an AAC .m4a, nothing further is lost and nothing recovered. For an Apple Lossless one the answer is less comfortable: the samples survive, but 24-bit ALAC is written out at 16 bits, so a hi-res master does give up depth. To check which you have, Get Info in Music or iTunes names the kind outright, and ffprobe reports the codec as alac rather than aac. If it is a 24-bit ALAC and you want it intact, FLAC is the honest target — it keeps all twenty-four.
Roughly 10 MB a minute at CD rate, whatever the .m4a weighed. From a 256 kbps AAC album that is about a tenfold increase; from Apple Lossless it is closer to double, because ALAC was already storing every sample and merely compressing them. A 96 kHz file is more again — the sample rate passes through unchanged, so a high-rate master stays high-rate and the arithmetic scales with it.
Yes — WAV is one of the formats this converter writes, so the reverse page exists at /wav-to-m4a/. The trip out is exact, because WAV discards nothing — it is the return to M4A that re-encodes. A round trip therefore costs one more generation rather than two, and the WAV in the middle was never an improvement on the M4A you started with.
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.