M4A to WAV converter
Your files are converted on your device. They are never uploaded.
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.m4a.aac.mp4.m4v
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Turn M4A voice memos and songs into uncompressed WAV that any editor or upload form accepts.
Speech-to-text services, older audio editors, sampling software, voice-over submissions, phone systems and some school or court portals insist on WAV. iPhones record Voice Memos as M4A, and music from Apple apps is M4A too. This page decodes the M4A, whether AAC or Apple Lossless, and writes a PCM WAV at the recording’s own sample rate, 16-bit or 24-bit, stereo or mono, optionally trimmed. It runs entirely in your browser, so interviews and private recordings stay on your device.
How to convert M4A to WAV
- Add the M4A files (on iPhone: Voice Memos › Share › Save to Files first).
- Pick 16-bit for most uses, Mono for speech and transcription, 24-bit only if your project uses it; set start and end to keep one part.
- Convert and download the WAVs, or a ZIP of all of them.
What happens to quality, size and metadata
For AAC files, the WAV is a perfect copy of the decoded sound: it can’t add detail that compression removed, but nothing more is lost, which is what editors and speech recognition want. For Apple Lossless M4As the WAV is identical to the original studio audio. Files grow a lot: a mono voice memo at 48 kHz 16-bit takes about 5.8 MB per minute, a stereo song at 44.1 kHz about 10 MB. The sample rate is kept as recorded. Tags and artwork from the M4A are not copied into the WAV. A single WAV can’t exceed 4 GB, so trim very long recordings.
- Test files
- 3
- Average input
- 246 KB
- Average output
- 2.1 MB
- Size change
- 8.59× larger
- Time per file
- 170 ms
M4A vs WAV
| Full name | M4A | WAV |
|---|---|---|
| Full name | MPEG-4 Audio | Waveform Audio File Format |
| Introduced | 2003 | 1991 |
| Defined by | MPEG · ISO/IEC 14496-14 + 14496-3 (AAC) | Microsoft & IBM · RIFF WAVE |
| Compression | Lossy or lossless | Lossless |
| Chrome / Edge | Yes | Yes |
| Safari | Yes | Yes |
| Firefox | Partly | Yes |
| Windows | Yes | Yes |
| iPhone / iPad | Yes | Yes |
| Android | Yes | Yes |
| Typical use | iPhone Voice Memos, music from Apple apps, and audio extracted from MP4 video. | Recording, editing and mastering audio, sound effects, and apps that need uncompressed sound. |
M4A M4A is an MP4 file that contains only sound, nearly always AAC (sometimes Apple Lossless). AAC sounds better than MP3 at the same bitrate. Apple devices use it for voice memos and music, but some older players, car stereos and websites accept only MP3.
WAV WAV is the RIFF audio format Microsoft and IBM introduced in 1991. It almost always stores uncompressed PCM samples, so nothing is lost, but one minute of CD-quality stereo takes about 10 MB. A single WAV file can’t be larger than 4 GB.
Sources for this table
- www.rfc-editor.org/rfc/rfc4337
- www.iso.org/standard/76383.html
- caniuse.com/aac
- developer.android.com/media/platform/supported-formats
- learn.microsoft.com/en-us/windows/win32/xaudio2/resource-interchange-file-format--riff-
- www.rfc-editor.org/rfc/rfc2361
- www.loc.gov/preservation/digital/formats/fdd/fdd000001.shtml
- caniuse.com/wav
Browser support data: caniuse.com, CC BY 4.0.
Without this site
Mac: in the Music app choose Music › Settings › Files › Import Settings › “WAV Encoder”, then select the item and choose File › Convert › Create WAV Version. Windows: Audacity can import M4A once its optional FFmpeg library is installed, then File › Export Audio as WAV. iPhone: GarageBand can import a voice memo and share the project as a WAV (“Uncompressed” quality). Android has no built-in option.
Troubleshooting
- Transcription service wants 16 kHz. We keep the original sample rate; most services accept 44.1 or 48 kHz too. Check their requirement.
- The WAV is huge. That is uncompressed audio. Choose Mono for speech to halve it, or trim the silence.
- Protected music files. Old DRM-protected iTunes purchases can’t be decoded in a browser.
- Recording is hours long. A 3-hour stereo recording is about 2 GB as 16-bit WAV. Choose Mono, trim, or split it into parts.
Questions and answers
How do I convert an M4A voice memo to WAV on iPhone?
In Voice Memos, tap the memo, then Share › Save to Files. Open this page in Safari, tap “Add files” › Browse and select the M4A. Choose Mono if it is speech, convert, and the WAV is saved to Downloads in the Files app. Nothing is uploaded.
Is WAV better quality than M4A?
WAV is uncompressed, so it never loses anything, but converting an AAC M4A to WAV can’t bring back what AAC removed. The WAV sounds the same as the M4A. It is the right format when software needs PCM or when you will edit and save repeatedly.
What WAV settings work for speech-to-text?
Mono, 16-bit, at the recording’s sample rate is accepted almost everywhere. Some services prefer 16 kHz; if yours requires it, resample in an audio editor after converting. Trimming long silences at the start and end saves processing time and upload size.
Can I convert M4A to WAV on Windows without installing anything?
Yes. Open this page in Edge or Chrome, add the files and press Convert. Windows can play M4A but has no built-in way to save it as WAV. The conversion happens in the browser, so the recording isn’t uploaded, and you can convert many files in one go.