How to convert M4A to WAV
- Select M4A, M4B, or audio-only MP4 files from your device storage.
- Optionally set channels to Mono or adjust the sample rate under More settings.
- Convert to WAV and download your uncompressed audio tracks or save them as a ZIP.
Prepping mobile voice notes for studio DAWs
Mobile journalists and podcasters regularly capture interviews, field ambience, and quick musical ideas on iPhones using the Voice Memos app, which stores recordings as M4A files. While great for storage, compressed M4A files can introduce scrubbing lag and decoding glitches inside editing software.
Converting those recordings into uncompressed 16-bit linear PCM WAV files creates clean, responsive audio stems ready for Pro Tools, Reaper, Logic Pro, or Audacity. You gain sample-accurate waveform editing, zero playback latency, and clean plugin processing across your session.
Optimizing audio for automated transcription tools
Speech-to-text engines, captioning tools, and transcription services frequently deliver their most accurate word alignment when provided with uncompressed WAV files. Compressed audio artifacts can sometimes confuse acoustic models, leading to dropped words or mistranscribed dialogue.
Unpacking M4A audio into 16-bit WAV provides transcription engines with clean audio samples. For speech-heavy recordings, setting Channels to Mono under More settings preserves vocal clarity while keeping uncompressed file sizes within reasonable limits.
Storage expectations and private on-device execution
Because WAV audio is uncompressed, files will expand considerably compared to their compressed M4A originals. A 5 MB voice recording will expand to approximately 30 to 50 MB as a 16-bit WAV, as stereo uncompressed audio requires about 10 MB per minute (and mono about 5 MB per minute).
All processing runs locally inside your browser via client-side WebAssembly, ensuring sensitive journalistic interviews, private voice notes, and unreleased song demos never leave your device. You can immediately send results to the volume booster or audio joiner.
Questions
How do I convert an iPhone Voice Memo to WAV?
Export the Voice Memo to the Files app on your iPhone, open this page in your mobile browser, select the M4A file, and convert it to WAV.
Why did my audio file get so much bigger?
M4A compresses audio heavily, whereas WAV stores uncompressed 16-bit linear PCM audio that requires roughly 10 MB per minute in stereo.
Can this convert M4B audiobooks too?
Yes. M4B audiobooks use the same MPEG-4 audio container and are decoded into uncompressed 16-bit WAV tracks.
Can converting compressed M4A to WAV recover lost acoustic detail?
No. While expanding AAC streams into PCM prevents compounding compression artifacts while editing, lost frequencies cannot be restored.