Convert M4A to WAV Online
Convert Apple M4A (AAC in MP4 container) to uncompressed WAV. Free, in your browser, no file uploads.
.m4a · up to 100 MB
What you can do
M4A to WAV: Apple audio ready for professional editing
iPhone voice memos
Convert iOS Voice Memos recordings to WAV for DAW editing.
100% private
AAC decoding happens in your browser. Your audio is never uploaded to any server.
Uncompressed PCM
WAV PCM 16-bit 44.1 kHz: the CD standard, ready for DAW, mastering, and hardware.
Instant
No queues or servers. Direct conversion in your browser in seconds.
How it works
Three steps, no hassle
Upload your M4A file
Drag or select your .m4a file. Up to 200 MB, no signup required.
AAC to PCM decoding
The AAC-LC codec inside the M4A is fully decoded in your browser. The result is uncompressed PCM audio ready for professional editing.
Download your WAV
Get a standard PCM 16-bit 44.1 kHz WAV file compatible with any DAW, audio editor, or device.
FAQ
Got questions?
Converting to WAV adds no further loss, but does not recover what already exists in the original M4A. M4A uses AAC-LC (Advanced Audio Coding - Low Complexity), a lossy codec that discards auditory information during compression. That loss occurred when the M4A was created — for example, when iTunes ripped a CD, or when the iPhone saved a voice memo. Converting to WAV decodes the AAC to uncompressed PCM, producing a file that sounds identical to the M4A but takes up much more space. WAV allows repeated editing without additional degradation, which is a real advantage over keeping the AAC format during editing.
There are three main scenarios where WAV is necessary. First, in professional DAWs: Pro Tools, Logic Pro, Ableton Live, Cubase, Reaper, and FL Studio work natively with WAV/AIFF. Although many import M4A, doing so implies internal decoding that can cause performance and plugin compatibility issues. Second, in CD mastering: the Red Book standard (Philips/Sony, 1980) defines CD audio as 16-bit linear PCM at 44.1 kHz, exactly the output format of this tool. Third, in professional hardware: digital mixers, samplers, portable recorders (Zoom, Tascam), and PA systems read WAV directly without needing AAC decoders.
The increase is very significant. A 16-bit 44.1 kHz stereo PCM WAV takes exactly 10.09 MB per minute (44100 samples/s × 2 channels × 2 bytes/sample × 60 s). A typical M4A at 256 kbps (iTunes Plus quality) takes approximately 1.92 MB per minute. The WAV will be 5 to 10 times larger than the M4A depending on the original bitrate. For a 5-minute iPhone voice memo (which may weigh 2–3 MB in M4A), the resulting WAV will be 40–50 MB.
M4A and MP4 are technically the same MPEG-4 Part 14 container developed by ISO/IEC. The .m4a extension is a convention introduced by Apple with iTunes in 2004 to indicate that the file contains audio only (no video), generally AAC. The .mp4 extension is used when the container includes video tracks (H.264, H.265) in addition to audio. At the byte level, both files use the same MPEG-4 atom structure (ftyp, moov, mdat, etc.). Players that support MP4 generally also support M4A, but some devices or platforms distinguish by extension, which can cause confusion.
Metadata in M4A is stored in the 'ilst' atom within the MPEG-4 structure, using tags like ©nam (title), ©ART (artist), ©alb (album), ©day (year), trkn (track number), and covr (album art in JPEG/PNG). WAV stores metadata in the RIFF INFO chunk (INAM, IART, IPRD, ITRK) or in an ID3 chunk. Conversion attempts to map the most common fields, but album art and extended fields like lyrics or comments may not be fully preserved in standard WAV.
Yes. The iOS Voice Memos app saves recordings in M4A format with AAC-LC codec, typically at 32 kbps mono for voice recordings (22.05 kHz or 44.1 kHz sample rate depending on iOS version). When sharing a voice memo via AirDrop, email, or iCloud, the resulting file is a .m4a. This format is ideal for recording because it balances quality and size, but can be problematic if you need to edit the recording in software that doesn't accept AAC.
Convert M4A to WAV: AAC decoding to uncompressed PCM
M4A is the audio format developed by Apple as part of the iTunes ecosystem, launched with iTunes 4 in 2003. Technically it is an MPEG-4 Part 14 container (ISO/IEC 14496-14) with the .m4a extension that Apple adopted to distinguish audio-only files from MP4 files containing video. The internal audio codec is AAC-LC (Advanced Audio Coding - Low Complexity), part of the MPEG-4 Audio standard (ISO/IEC 14496-3), jointly developed by Fraunhofer, AT&T Bell Labs, Sony, and Dolby as the successor to MP3. AAC offers perceptually superior quality to MP3 at equivalent bitrates thanks to technical improvements including longer transform windows (2048 points vs. MP3's 576/1152), better psychoacoustic modeling, and support for up to 48 audio channels. Apple uses M4A in three main contexts: the iTunes Store (now Apple Music) sells tracks at 256 kbps AAC-LC in the format known as iTunes Plus, the iOS Voice Memos app records directly to M4A, and GarageBand and Logic Pro X exports use M4A as a high-quality interchange format.
Converting M4A to WAV is technically a decoding operation: the AAC-LC stream is decoded to uncompressed PCM (Pulse Code Modulation), the digital audio representation format that directly stores sampled waveform amplitudes without any perceptual transformation. The result is WAV with 16-bit PCM specification at 44.1 kHz, equivalent to CD quality under the Red Book standard (Philips and Sony, 1980). This specification implies an amplitude resolution of 65,536 levels (2^16) and a maximum representable frequency of 22.05 kHz (Nyquist theorem), slightly above the human hearing limit of 20 kHz. It is essential to understand that this conversion does not restore the original source quality: if the M4A was created by compressing a CD (with loss of auditory information during AAC encoding), the resulting WAV will contain that same loss. What WAV provides is an editable container without compression that allows repeated processing without cumulative degradation.
The most important use cases for M4A to WAV conversion are concentrated in music production and professional audio. Voice memos recorded on iPhone — journalistic interviews, musical ideas, meetings — often need to be edited in DAWs that work better with native WAV. Tracks purchased from iTunes before the streaming era (millions of users have M4A libraries from the 2003–2015 period) need conversion for use in DJ projects (Serato, Traktor, rekordbox handle WAV better than M4A in some scenarios), in games requiring WAV audio assets, or in PA systems. GarageBand on iOS exports projects as M4A, and producers who need to continue work in Pro Tools or Ableton on desktop require WAV. Convertir.ai performs the complete AAC decoding in the browser using WebAssembly without sending audio to any server, guaranteeing absolute privacy for personal or confidential recordings.