Rescreen / Free tools / M4A to WAV

M4A to WAV converter

Drop an M4A here for a WAV made in your browser: the same sound, never better, in a bigger file.

Drop an M4A file here

or choose one from your device

Up to 2.0 GB. Stays on your device.

How to convert M4A to WAV

Three steps, all on this page.

Choose your M4A
Choose or drop an M4A file. The page reads what is inside and checks that this browser can convert it before anything starts.
Convert to WAV
Pick the options you want, then press Convert to WAV. The sound is decoded into plain, uncompressed samples, which takes seconds even for a long file.
Check and download
The new file is opened again and checked against the original before it is offered. Listen in the preview, then download it.

What changes from M4A to WAV

An M4A is an MPEG-4 file with sound only: MDN lists audio/mp4 with the extensions .mp4 and .m4a. MP4 itself comes from Apple’s QuickTime file format. Source
AAC is lossy, from 8 to 96 kHz at up to 512 kbps. Apple Lossless (ALAC) is lossless: 16, 20, 24 or 32 bits, up to 384 kHz and 8 channels, and files up to 45–60% smaller than uncompressed. Source
Of the major browsers only Safari plays Apple Lossless; Chrome, Edge, Firefox and Opera do not. Source
WAV was developed by Microsoft and IBM and first released in 1991. Nearly all WAV files hold linear PCM: uncompressed, the highest fidelity, at the cost of larger files. Source
Apple: if you compress a song and it loses data, you cannot uncompress it to get the data back. Converting from a compressed to an uncompressed format does not improve its quality; the file only takes more space. Source
The Music app on a Mac converts a song to WAV: set Import Using in Settings › Files › Import Settings, then File › Convert › Create WAV Version. Both versions stay in the library. Source
Voice Memos on a Mac records Compressed (lower quality, smaller files) or Lossless (high quality, larger files), set in Voice Memos › Settings › Audio Quality. Source
Audacity exports WAV as signed 16-bit PCM by default, which its manual calls CD quality, and a WAV cannot exceed 4 GB. It opens M4A once the optional FFmpeg library is installed. Source

M4A file

M4A (MP4, sound only)

Picturenone
SoundAAC or ALAC

WAV file

WAV

Picturenone
Sound16-bit PCM, uncompressed

Who converts M4A to WAV

Mostly people with a recording from an iPhone or Mac. Voice Memos and the Music app both give you M4A files, and the next step often wants WAV: a DAW or video editor, a transcription service or captioning tool, a phone system that plays greetings from WAV, a sampler, or an upload form that lists WAV and nothing else. Podcasters converting an interview recorded on a phone are a large share of them.

AAC or Apple Lossless: what is inside your M4A

An M4A is a container, and two very different kinds of sound go in it. Nearly every M4A is AAC, the lossy format the iTunes Store, Apple Music downloads and Voice Memos on the Compressed setting use. Some are Apple Lossless (ALAC): CDs imported with the Apple Lossless encoder, studio and archive copies, and Voice Memos set to Lossless. Both end in .m4a, so the name alone does not tell you which you have.

This page tells you as soon as you choose the file: the line under its name says AAC audio or Apple Lossless (ALAC) audio. In the Music app, select the song and press Command-I; the File tab shows its kind. The difference decides what the WAV can be.

What happens to the sound

From AAC, the WAV holds the sound the AAC decodes to, the same samples your speakers get when you play the M4A. It sounds exactly like the M4A, no better and no worse: what the AAC encoder left out is gone, and no converter can put it back. What you gain is a file every editor reads the same way, and one you can edit and export again without another lossy encode in between.

From Apple Lossless, nothing was left out to begin with. A 16-bit Apple Lossless file kept at its own rate and channels becomes a WAV with exactly the same samples, so it is a perfect copy, only bigger. This page checks that: its decoder gives the same samples as ffmpeg’s, bit for bit.

A 24-bit Apple Lossless file (a studio master, or a Lossless voice memo from a Mac) is decoded without loss and then written as 16-bit, the depth of a CD and of every WAV this page makes. If you need to keep all 24 bits, use Audacity or ffmpeg, below.

No browser decodes Apple Lossless on its own, which is why many online converters refuse it or send it to a server. This page decodes it with its own code, in your browser, in Chrome, Edge, Firefox and Safari alike.

Which sample rate and channels to choose

Every WAV this page makes is 16-bit PCM, the format nearly every program reads. You choose two things.

Sample rate: Keep the original (the default) writes the M4A’s own rate. Nothing is resampled, so it is the closest copy.
48,000 Hz for a video editor’s timeline or a 48 kHz DAW project, and 44,100 Hz for music and CDs, so the other program does not resample on import.
8,000 Hz for phone systems. Speech stays clear and the file shrinks to a fraction of the size; music will sound like it is coming down a phone line.
Channels: Keep the original, or Mono to mix the two channels into one. Mono halves the WAV, and suits a voice recording going to a transcription service or a phone system. Stereo puts a mono voice memo on both channels for a tool that insists on two.

How big the WAV will be

A WAV grows by the same amount every minute, whatever is in it: at CD settings (44,100 Hz, 16-bit, stereo) about 10 MB a minute, at 48,000 Hz mono about 5.5 MB. A 256 kbps AAC song grows about five and a half times; an Apple Lossless one roughly doubles, because Apple Lossless already keeps everything and only packs it more tightly.

The page builds the WAV in your browser’s memory and makes files up to 2 GB, about three and a half hours at CD settings. For something longer, choose mono or a lower rate, and the page tells you before it starts if the result would not fit.

WAV setting	3:00 song, AAC	3:00 song, Apple Lossless	1:00 voice clip
Original rate	30.3 MB in 0.4 s	30.3 MB in 1.1 s	5.5 MB in 0.1 s
48,000 Hz, stereo	33.0 MB in 0.6 s	33.0 MB in 1.5 s	11.0 MB in 0.3 s
8,000 Hz, mono	2.7 MB in 0.5 s	2.7 MB in 1.3 s	938 KB in 0.1 s

The song is three minutes of 44,100 Hz stereo test music made with ffmpeg 7.1, as a 256 kbps AAC M4A (4.9 MB) and as Apple Lossless from afconvert (13.3 MB); the voice clip a one-minute 48,000 Hz mono AAC M4A at 64 kbps (485 KB). Converted with this page in Chromium 156 on an M1 MacBook Pro, macOS 15.8.1. At the original rate the AAC song took 1.4 s in Safari 27.0 and 1.0 s in Firefox 157; the Apple Lossless one 1.2 s and 1.5 s. Every WAV came out the length of the original.

When not to convert

Do not convert in the hope of better sound. A WAV made from an AAC M4A sounds exactly like the M4A, in a file five or more times the size. For a better copy, go back to the source: the CD, the original recording, or a lossless download.

If the next step already takes M4A, keep the M4A. Most video editors, podcast hosts and transcription services do, and so does Audacity once its FFmpeg library is installed; editing an M4A and exporting it as WAV loses nothing more than converting first would.

To keep a 24-bit Apple Lossless file at 24 bits, use Audacity or ffmpeg instead: this page writes 16-bit WAV only.

Other ways to convert M4A to WAV

Music app Mac

Choose Music › Settings, click Files, then Import Settings.
Set Import Using to WAV Encoder and click OK.
Select the songs, then choose File › Convert › Create WAV Version. For files not in your library, hold Option while opening the File menu, choose Convert › Convert to WAV, and pick the files.
The WAVs appear in your library next to the originals; drag them to the desktop to use them elsewhere.

Handy for songs already in your library, Apple Lossless included. Set Import Using back afterwards, since it also applies to CDs you import.

iTunes Windows

Choose Edit › Preferences, click General, then Import Settings.
Set Import Using to WAV Encoder; choose Custom under Setting to pick the sample rate and channels.
Select the songs, then choose File › Convert › Create WAV Version.

The same idea as the Music app, and it reads Apple Lossless too.

Audacity Windows, Mac or Linux

Install the FFmpeg library for Audacity (Edit › Preferences › Libraries shows whether it is found); Audacity needs it to open M4A.
Open the M4A with File › Open.
Choose File › Export Audio, set the format to WAV, and choose the channels, sample rate and encoding (Signed 16-bit PCM is the default; Signed 24-bit PCM keeps a 24-bit file whole).
Choose Export.

Free and offline, and you can trim, fade or clean up the sound before saving.

ffmpeg Any computer, from the command line

Install ffmpeg (on a Mac with Homebrew: brew install ffmpeg).
Run ffmpeg -i input.m4a -c:a pcm_s16le output.wav for a 16-bit WAV at the M4A’s own rate and channels.
For a 24-bit Apple Lossless file, use -c:a pcm_s24le to keep every bit; for a phone system, add -ar 8000 -ac 1.

The quickest way to convert a whole folder, and it reads AAC and Apple Lossless alike.

Frequently asked questions

Does converting M4A to WAV improve the quality?

No. From an AAC M4A, the WAV holds exactly what the AAC decodes to, so it sounds the same in a much bigger file. From Apple Lossless there was nothing missing to begin with, and the WAV is the same sound, sample for sample.

How do I convert M4A to WAV for free?

Drop the M4A on the converter at the top of this page and press Convert to WAV. It is free, with no sign-up or watermark, and runs in your browser. The Music app on a Mac, iTunes on Windows, Audacity and ffmpeg can do it for free too.

Do I need to convert an M4A to WAV before editing it?

Usually not: most editors open M4A, and Audacity does once its FFmpeg library is installed. Converting helps when an editor or plug-in will not take M4A, or when you want every edit to start from the same uncompressed samples. Either way, export the finished edit once, at the end.

How do I know if my M4A is AAC or Apple Lossless?

Choose it on this page: the line under the file name says AAC or Apple Lossless (ALAC). In the Music app, select it and press Command-I to see its kind. A lossless file is usually several times larger for the same length.

Which sample rate should I use for a transcription service?

Keep the original rate unless the service names one: a higher rate adds no detail, and a lower one only saves space. Choose Mono for a single speaker to halve the upload. For a phone system, choose 8,000 Hz and Mono.

Why is the WAV so much bigger than the M4A?

Because nothing in it is compressed. CD-quality WAV is about 10 MB a minute, while a 256 kbps AAC song is under 2 MB a minute. Apple Lossless is already about half the size of the WAV, so it only roughly doubles.

Is my file uploaded?

No. Your M4A is read, converted and checked on your own computer, so there is no upload and no queue. In Chrome and Edge on a computer files of any size work, written straight to a file you choose; in other browsers, files up to 2.0 GB. We count anonymous page views and whether a conversion worked; when one fails, the event also carries the step, your browser’s error and the file’s codecs, size and length in broad bands, never the file or its name. If a conversion fails you can choose to send us the file, which is deleted within 30 days. See the privacy policy.

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