OneTaskBy Tim King · Updated
M4A to WAV
16-Bit or 24-Bit PCM Output From iPhone Voice Memos, iTunes and Recorder Apps
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How the M4A To WAV works
Drop in an M4A, such as an iPhone voice memo or an iTunes track, and download it as an uncompressed WAV. This M4A to WAV converter uses your browser's AAC decoder and writes 16-bit or 24-bit PCM that opens in every editor and transcription tool. Nothing is uploaded.
M4A to WAV: unpacking AAC into raw samples
An M4A is an MPEG-4 audio container. Usually it holds AAC, a lossy codec that keeps files small by discarding detail you are unlikely to hear; sometimes it holds Apple Lossless (ALAC). WAV holds plain PCM samples with no compression. Converting M4A to WAV decodes the audio once and stores the result exactly, which is what editors, DAWs, speech recognition services and broadcast systems want. It cannot recover what AAC removed, but nothing further is lost.
What changes and what is lost
- Lossy AAC source: the WAV sounds the same as the M4A, just five to ten times larger.
- ALAC source: the conversion is lossless both ways. Choose 24-bit if the ALAC was 24-bit.
- Sample rate: iPhone voice memos are recorded at 48 kHz AAC, and iTunes music at 44.1 kHz. The browser decodes at its own audio rate, shown in the stats.
- Metadata: titles, chapters and artwork in the M4A are not written to the WAV.
- Encoder delay: AAC adds about 2,112 samples of priming silence. Safari trims it using the file's iTunSMPB note; other browsers may leave a few milliseconds at the start.
Browser support for M4A decoding
AAC in M4A decodes in Chrome, Edge, Safari on macOS and iOS, and Firefox on Windows and macOS. Firefox on Linux relies on system FFmpeg libraries. Apple Lossless decodes reliably only in Safari, so open ALAC files there if another browser reports that the file cannot be decoded.
How to read the stats
Source lists channels, decoded sample rate, seconds and original size. Output is the bit depth chosen and Output size is the exact size of the WAV in megabytes. Voice memos are mono, so their WAVs are half the size of a stereo track of the same length.
To share a smaller copy, use M4A to MP3. The MP3 to WAV and FLAC to WAV pages handle the other common sources, and the sample rate converter changes the rate of the finished WAV.
FAQ
How do I convert an iPhone voice memo to WAV?
Share the memo from the Voice Memos app to Files, then drop the saved M4A on this page and click export. The memo is decoded in your browser and saved as a mono WAV, which transcription services and audio editors accept directly.
Is M4A to WAV conversion lossless?
It loses nothing further, but it cannot undo the AAC compression already in most M4A files. If the M4A holds Apple Lossless audio, the WAV is a bit-exact lossless copy, provided you choose a bit depth at least as high as the source.
Why can my browser not open this M4A?
The file probably contains Apple Lossless, which Chrome and Firefox usually cannot decode, or it is a DRM-protected purchase. Try the same file in Safari. Protected .m4p files cannot be converted by any browser tool.
Is my M4A uploaded anywhere?
No. The file is decoded, processed and encoded inside your browser with the Web Audio API. Nothing is sent to a server, so it works offline once the page has loaded and your audio stays private.
See also: all Audio & Video tools, Units, Images, Documents, Data & Code.
Related tools
M4A To MP3
Convert iPhone and iTunes M4A audio to MP3 in your browser.
MP3 To WAV
Turn an MP3 into an editable 16- or 24-bit WAV.
FLAC To WAV
Unpack lossless FLAC into a 16- or 24-bit WAV.
Audio To WAV
Convert MP3, M4A, FLAC or OGG to 16- or 24-bit WAV.
Sample Rate Converter
Resample audio to 44.1, 48, 16 kHz or any common rate.