AnyFormat

00 M4A → WAV

M4A to WAV

The format speech models and editors expect.

Drop files or a folder here

or choose from your device · paste with ⌘V / Ctrl+V

.m4a .m4b

03Options 4

Right for speech, wrong for music. At a fixed quality the file size does not change — but mono tolerates a much lower quality than stereo, so combine the two to actually shrink the file.

Leave at 0 for the whole file.

0 means run to the end.

  • No upload The conversion runs in this tab. Your file never travels — not to us, and not to the advertising.
  • No sign-up, no email, no daily cap There is no account system to sign up to.
  • No size limit we invented Only your device's memory — about ~2 GB on a desktop browser, ~400 MB on a phone.
  • Turn your Wi-Fi off and convert anyway The conversion needs nothing but this page. Ads will not load without a connection; your file will still convert. That is the whole claim, and it takes five seconds to check.

Decodes M4A into uncompressed WAV. The usual reason is transcription: nearly every speech model wants WAV, and an iPhone voice memo is M4A.

Settings for transcription

Mono at 16 kHz is what most speech-recognition models expect, and it is what they downsample to internally anyway. Choosing it here produces a file a fraction of the size with no loss of recognition accuracy.

For music or anything where the full frequency range matters, keep the original sample rate and channels.

It is still a lossy source

M4A is AAC, which is lossy. The WAV is an uncompressed copy of that — larger, not better. What it avoids is a second lossy generation during editing.

Mono at 16 kHz is the right shape for speech

Speech recognition models are almost all trained on 16,000 samples a second, mono. Feeding one a 48 kHz stereo file does not improve the result — the model resamples it down anyway, and doing that on their side sometimes costs you a slot in a queue you are paying for. Converting to mono also halves the file, and for a recording made on a phone the two channels usually carry the same microphone. Music is the opposite case: keep both channels and the full rate, because everything you discard here is gone.

Tags do not survive the crossing

An M4A carries title, artist, album, artwork and whatever else iTunes put in it. WAV has no agreed place for any of that. There is a RIFF INFO chunk and there is an ID3 chunk, and support for both is inconsistent enough that a player showing your metadata and a player ignoring it are equally standards-compliant. So the audio comes across and the labelling does not. For a file heading into an editor or a transcription service that does not matter; for a music library it means keeping the original.

Other names for this

Also searched as “voice memo to wav”, “convert m4a to wav”.

Questions

What settings does Whisper or similar want?
Mono at 16 kHz. Both options are on this page, and the resulting file is far smaller.
Will it improve the recording?
No. It is an uncompressed copy of lossy audio.
Is my file uploaded?
No. The demuxing, decoding and encoding all happen in this tab using the browser’s own media stack plus a WebAssembly encoder. A recording can be an interview, a lecture, a private call — none of it is transmitted. Turn your Wi-Fi off after the page loads and it still works.
How large a file can I convert?
There is no imposed limit, only your device’s memory — around 2 GB in a desktop browser and 400 MB on a phone, since the file is held in memory while it converts. A two-hour video converts in well under a minute on a laptop.
Can I convert several files at once?
Yes. Drop as many as you like, or a whole folder. Each keeps its original name with the new extension, and you can download them individually or as a ZIP.