M4A to WAV
Turn M4A recordings, like Voice Memos, into WAV files. Nothing is uploaded.
Drop M4A files here
Converted on your device. Files are never uploaded.
Up to 20 files at a time.
M4A files from iPhones, Voice Memos and iTunes are compact, but audio editors, samplers and some upload forms want WAV. FormatJet decodes the AAC audio and writes an uncompressed WAV in your browser, so interviews, lectures and personal recordings stay on your device the whole time.
About the formats
M4AM4A audio
M4A is an MP4 file that holds only audio, usually AAC. iPhones, iTunes and voice recorders use it; files are smaller than MP3 at the same quality, but some players and sites only take MP3.
WAVWAV audio
WAV holds uncompressed audio, as recorded. It keeps every detail and opens in any audio editor, but a minute of CD-quality stereo takes about 10 MB.
Converted with Mediabunny, Browser audio decoder (WebCodecs), Media engine (FFmpeg).
Questions
Can I edit a Voice Memo as WAV?
Yes. Voice Memos are stored as M4A; once converted to WAV, a memo opens in any audio editor, where you can trim it, clean it up or mix it.
Is anything lost going from M4A to WAV?
No further compression is applied. The WAV keeps the decoded audio as plain samples, so it sounds like the M4A, but what the AAC encoder removed when the M4A was made stays missing.
Will an audio-only .mp4 work here?
Yes. A file with only audio in it that was saved with .mp4 at the end is the same kind of file as an M4A, and this page accepts it.
Can I convert a batch of memos?
Yes, up to 20 recordings at once. Each one is saved as a WAV under its original name, and you can download them separately or as a ZIP.
M4A to WAV with the API
The conversion API opens later this year.
curl https://api.formatjet.com/v1/convert?to=wav \
-H "Authorization: Bearer fj_test_…" \
-F file=@input.m4a -o output.wav