Convert M4A and AAC files from iTunes, Voice Memos or an Android recorder into MP3s that play on any device, with tags and cover art carried across. Nothing is uploaded.
✓ No upload — runs in your browser
✓ Batch convert & ZIP download
✓ Free, no sign-up
Drop M4A, AAC, MP4 files here
or
Free: up to 5 files per batch · Files never leave your device · Paste from the clipboard works too
The free plan converts 5 files per batch. Only the first 5 were added.
Get Pro for US$9 once — unlimited batches and no ads, forever.
1
Waiting…
Private by design
Your files are processed by your own device using WebAssembly and your browser's built-in codecs. Nothing is uploaded, logged or stored.
Fast & offline-ready
No queue, no waiting for a server. Once the page has loaded it even works without a connection.
Works everywhere
Chrome, Edge, Firefox and Safari on Windows, macOS, Linux, Android and iOS. No app to install.
What an M4A file actually is
The .m4a extension is Apple's label for an MP4 container that holds audio only, almost always encoded with AAC. Technically it is the same thing as the soundtrack of a video, just without the picture. The format is excellent, but it carries an Apple reputation that older car stereos, cheap MP3 players, some Windows programs and plenty of web upload forms have never caught up with. MP3, in contrast, is the one audio format that every device made this century understands.
Where your M4A files come from
Source
Typical encoding
Sensible MP3 bitrate
Voice Memos on iPhone, iPad and Mac
AAC, mono, around 64 kbps
96–128 kbps
iTunes Store purchases
AAC, 256 kbps stereo
256–320 kbps
Samsung Voice Recorder and Google Recorder on Android
AAC, mono or stereo
96–128 kbps
GarageBand, Logic and iMovie audio exports
AAC, 128–256 kbps
192–320 kbps
Audio shared from an iPhone via WhatsApp or iMessage
AAC, varies
128–192 kbps
A good rule: match the bitrate to the source. Encoding a 64 kbps voice memo at 320 kbps makes a file five times larger that sounds exactly the same.
When MP3 is the better choice
A USB stick for a car head unit or a hi-fi that lists MP3 and WMA but not AAC.
Uploading a lecture or interview to a learning platform or transcription service that only accepts MP3.
Sending a voice memo to someone on Windows or Android who does not want to install anything.
Attaching audio to a WordPress post, a podcast feed or an email where MP3 is the safe default.
Loading sound into older editing or presentation software.
How Tinyvert converts it
The AAC stream is decoded by your browser, using the codecs the operating system ships, and the samples are handed to the LAME MP3 encoder compiled to WebAssembly. Mono stays mono and the sample rate is unchanged, so a 44.1 kHz voice memo produces a 44.1 kHz MP3. Metadata written by iTunes or the recording app, including the cover image, is carried over. Conversion of a typical track takes a few seconds, and five files run in one batch with a progress bar for each. Large files are limited by your device's memory, which matters only for very long recordings on a phone.
Privacy for personal recordings
Voice memos tend to contain things you would not post online: meetings, medical notes, song ideas, a child's first words. The conversion happens entirely in your browser, nothing is uploaded or stored, and the page keeps working offline after the first use. Need the reverse? MP3 to M4A goes back the other way, and the Audio Converter turns M4A into WAV, FLAC or OGG. Our guide to MP3, WAV and FLAC explains when a lossy format is good enough.
How to convert m4a to mp3 — step by step
1
Drop up to five M4A, AAC or audio-only MP4 files into the drop zone, or click "Choose files".
2
Choose a bitrate from the Bitrate menu; the default of 192 kbps suits both music and speech.
3
Each file shows a progress bar while it is decoded and encoded to MP3 on your device, then the size change.
4
Download the MP3s individually or as a ZIP, or tap Share on a phone to hand the file to another app.
Frequently asked questions
What is the difference between M4A and MP3?
M4A is AAC audio stored in an MP4-style container, the format Apple adopted for iTunes and Voice Memos. AAC is slightly more efficient than MP3 at the same bitrate, but MP3 is understood by far more devices.
Why will songs from Apple Music not convert?
Tracks downloaded through an Apple Music subscription are protected with DRM and no converter can decode them. Songs bought from the iTunes Store (DRM-free since 2009) and your own recordings convert without trouble.
Will the quality drop?
Slightly, because AAC is decoded and re-encoded as MP3. For iTunes purchases at 256 kbps choose 256 or 320 kbps and nobody will hear the difference; for voice memos 96 or 128 kbps is more than enough.
Are album art and tags kept?
Yes. Title, artist, album and embedded cover art are copied from the M4A into the MP3's ID3 tags, so your library stays organised.
Can I convert WhatsApp voice notes?
WhatsApp's own voice messages are Opus files, so use OGG to MP3 for those. Recordings shared from an iPhone through WhatsApp, iMessage or Mail usually arrive as .m4a and belong here.
Does it accept .aac files?
Yes. Raw .aac streams and audio-only .mp4 files are accepted along with .m4a.