Audio
Convert M4A to WAV on Mac
To convert M4A to WAV on a Mac, open Terminal and run afconvert in.m4a out.wav -d LEI16 -f WAVE. It is built into macOS, free, and writes a standard 16-bit WAV. The Music app can do it too, with a one-time setting change.
One warning first. M4A is usually lossy AAC. WAV is uncompressed. The conversion makes a file about twelve times bigger in our test, but it does not bring back detail the AAC encoder already threw away.
How do I convert M4A to WAV in Terminal?
Use afconvert, Apple’s own audio converter. It decodes the AAC and writes PCM samples into a WAV container:
afconvert in.m4a out.wav -d LEI16 -f WAVELEI16 means little-endian 16-bit integers, the CD-quality format almost every editor and device accepts. For a whole folder:
for f in *.m4a; do afconvert "$f" "${f%.m4a}.wav" -d LEI16 -f WAVE; doneThe sample rate and channel count carry over from the source. Add -r 48000 only if your video editor wants 48 kHz. See man afconvert for the rest.
Can the Music app convert M4A to WAV?
Yes. Open Music, go to Music > Settings > Files > Import Settings, set Import Using to WAV Encoder, and click OK. Add the M4A to your library, select it, then choose File > Convert > Create WAV Version. The new WAV appears next to the original in the library.
It works, but it fills your library with duplicates and the setting stays changed until you switch it back. For files that are not part of your music collection, the Terminal command is cleaner.
How much bigger is a WAV than an M4A?
We built a 30-second stereo fixture at 44.1 kHz, encoded it to AAC M4A at 128 kbps with afconvert, then converted the M4A back to WAV with the command above.
| File | Size in bytes | Note |
|---|---|---|
| Original WAV (16-bit) | 5,292,078 | The reference |
| M4A, AAC 128 kbps | 422,562 | About 8% of the WAV |
| WAV from the M4A, 16-bit | 5,296,096 | Same duration, 30.000 s |
| WAV from the M4A, 24-bit (LEI24) | 7,942,096 | Bigger, no extra detail |
The round-trip WAV is 4,018 bytes larger than the original: the extra is header data, not audio. The 24-bit file is 50% larger and holds exactly the same information, because the AAC source never had 24-bit detail. Use 16-bit unless your project is 24-bit and the editor insists.
Does converting M4A to WAV improve the quality?
No. A WAV made from lossy AAC is a bigger copy of the same damage. The converted file will not sound better, and its checksum will not match the pre-AAC original. Do not convert back and forth either: each lossy encode adds new loss.
Converting is still useful. Many editors, samplers and broadcast tools want PCM, and decoding once to WAV means they do not decode on every playback. If an M4A is Apple Lossless instead of AAC, the WAV is a true bit-for-bit copy of the audio. Check with afinfo file.m4a. To go the other way, see how to convert M4A to MP3 on Mac.
When is Smol the wrong tool for this?
For a handful of files, afconvert is enough, and you do not need to install anything. If you convert one voice recording a month, use the command above and stop reading.
Smol earns its $29 (once, one Mac) when conversion is routine. Drag in a mixed folder of M4A, MP3 and FLAC files, choose WAV, and get per-file progress, with a Finder Quick Action for right-click jobs. Nothing is uploaded. It writes copies next to the originals by default. The buy page has the details, and our audio converter roundup compares the free options. WAV files are large, so after editing, compressing the audio is the next step.
How we checked this
Converted a synthetic 30-second stereo fixture from AAC M4A to 16-bit and 24-bit WAV with afconvert on macOS 27.0.1, measured sizes with stat and duration with ffprobe. Facts last checked . We make Smol, so treat our claims about it with the same care as any vendor’s, and see our editorial policy.
M4A to WAV: common questions
Is converting M4A to WAV lossless?
The conversion itself loses nothing, but the M4A was usually already lossy. AAC discards audio detail when it is encoded, and no WAV can restore it. You get an uncompressed file that sounds identical to the M4A, only much larger. Apple Lossless M4A files are the exception: they convert to WAV with no change in the audio.
Can QuickTime or Preview convert M4A to WAV?
Not directly. QuickTime Player exports audio as M4A, and Preview does not handle audio. The free routes on a Mac are the afconvert Terminal command and the Music app with its import encoder set to WAV. Both work offline and leave the original untouched.
How do I convert a Voice Memo to WAV?
Voice Memos are M4A files. Drag the recording out of the Voice Memos window into a Finder folder, then run afconvert on the copy. A voice recording gains nothing from 24-bit, so keep LEI16. The WAV will be far larger than the memo, which is normal.
Why is my WAV so much bigger than the M4A?
WAV stores every sample uncompressed. Stereo 44.1 kHz 16-bit audio is about 176 KB per second, whatever the content. A 128 kbps AAC file stores roughly 16 KB per second. In our test, 30 seconds went from 422,562 bytes in M4A to 5,296,096 bytes in WAV.
Should I pick 16-bit or 24-bit WAV?
Pick 16-bit for anything made from an M4A. AAC does not contain 24-bit detail, so a 24-bit WAV only adds size. In our test the 24-bit file was 7,942,096 bytes against 5,296,096 for 16-bit, with the same audio. Choose 24-bit only when your editing project requires it.
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