Convert M4A to WAV in your browser

For the transcription tool or editor that only takes PCM. If it is speech, drop to 16 kHz mono: a fifth of the size and no worse a transcript.

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M4A to WAV options

Sample rate (Hz) 44100

For speech, 16 kHz is what every speech recogniser resamples to anyway, and picking it here cuts the file by two thirds before you start. For music, leave it at 44.1 kHz. We never upsample.

Downmix to mono Off

One channel instead of two, halving the file. A voice memo or a single-microphone meeting recording is effectively mono already, so this usually costs nothing at all.

Strip tags and cover art Off

Off by default. An M4A carries title, artist and often cover art; WAV can hold the text ones in a LIST INFO chunk, and there is no size reason to drop them.

Convert to a target size Off

PCM size is rate x channels x 2 bytes x duration, so we pick the highest sample rate that fits your figure given the mono setting, and say so if even 16 kHz mono cannot reach it.

How to convert M4A to WAV

01

Drop the M4A files

Voice memos, interviews, Zoom or Teams recordings. Nothing is uploaded, which is the point when the file is a recording of other people.

02

Match the settings to the job

16 kHz mono for anything going to a transcriber. 44.1 kHz stereo if you are editing music. We never upsample, so a higher figure than the source does nothing.

03

Save the WAV

A plain 16-bit PCM WAV that Whisper, Audacity, Premiere, Reaper and every research transcription pipeline will take without a codec argument.

Why does anything still demand a WAV?

Because PCM needs no decoder. A WAV header says how many channels, at what rate, at what bit depth, and then the samples follow. Any program that can read bytes can read it correctly, with no codec library, no licensing, and no risk of two decoders disagreeing about the same file. That is why speech recognition tools, research software, DAWs and broadcast delivery specs still ask for it in 2026, decades after it stopped being a sensible way to store music.

M4A is the opposite: a container holding an AAC stream, which needs a real decoder and, historically, a patent licence. Plenty of software still refuses it or handles it badly, and on Linux and in Python pipelines in particular it is common to hit a tool that will simply not open one.

Since your M4A is already lossy, converting to WAV recovers nothing. It gives you a file that everything opens, at roughly ten times the size for full-rate stereo. The way to keep that reasonable is to match the settings to the work: speech recognition resamples everything to 16 kHz mono internally, so handing it 44.1 kHz stereo means writing five times as many bytes for it to throw away immediately.

M4A to WAV FAQ

What settings should I use for transcription?

16 kHz with mono on. Every speech recognition system, Whisper included, resamples to 16 kHz mono before it does anything else, so giving it that directly costs you no accuracy and makes the file about a fifth the size. Higher settings do not produce a better transcript.

Will the audio sound better as a WAV?

No. The M4A already discarded audio permanently when it was encoded and none of it comes back. The WAV is a faithful uncompressed copy of what is left, which is exactly what a tool that demands PCM needs, and is not an improvement.

Why is the file so much bigger?

PCM stores every sample at full width with no compression. Size is rate x channels x 2 bytes x duration and the content makes no difference. An hour of 44.1 kHz stereo is about 600MB; the same hour at 16 kHz mono is about 115MB.

Does this work with iPhone voice memos?

Yes. Voice Memos records M4A, and the file it shares is exactly what this page reads. For a voice memo, 16 kHz mono is almost always the right choice.

Is my meeting recording uploaded?

No. Everything happens in this tab: the M4A is decoded and the WAV is written by your own browser. For a recording of colleagues or an interview subject that is not a detail, it is the reason to use this rather than a site that takes your file.

What about M4B or M4R files?

Same container, different extension. Rename to .m4a and they convert here. An M4B audiobook will produce a very large WAV, so lower the sample rate and turn mono on unless you have a reason not to.

Are my M4A files uploaded to convert them?

No. The M4A is decoded and the WAV is written by your own browser, in this tab. There is no upload endpoint in the site for a file to go to, which you can check in your network tools: convert something and watch that no request carries it. Disconnect from the network after the page loads and it still works.