Your browser opens the file.
The M4A is decoded by your browser's own decoder, on this device, at 44.1 kHz, the sample rate of a CD.
SOLIPSIUM Super resolution audio engine
Free audio tool
Convert M4A to MP3, voice memos included.
Turn an iPhone voice memo or any M4A file into an MP3 or WAV in your browser, with no sign-up. Then see whether the recording itself is clear.
Drop an M4A file here
Your browser converts it to MP3 or WAV on this device. It stays on your device until you ask for a repair.
M4A, MP4, AAC, MP3, WAV, OGG, Opus, WebM or FLAC, up to 30 minutes or 200 MB. CAF files open in Safari.
Ready to convert
The MP3 folds this file's channels into stereo; the WAV keeps every channel.
Is the recording itself clear?
Converting does not clean the sound. Solipsium's free try is built for speech: the check below looks in your browser for background noise, hum, clipping, dropouts and muffled sound, and you can hear the first 20 seconds of a voice recording repaired with no account.
Your first 20 seconds
After signing up, drop the same file into the editor to repair all of it.
What Solipsium hears
Make a free account to repair the whole recording
Then drop the same file into the editor. Scans and short repairs are free.
How it works
M4A to MP3 is lossy to lossy.
An M4A file usually holds AAC sound, which already left some detail out to save space. Converting decodes that sound and compresses it again as MP3, in its own way, so a little more is lost. Choose 192 kbps or more and the second loss stays small.
It is compressed again as MP3.
The MP3 has a constant bitrate: 192 kbps unless you choose 128, 256 or 320. A higher bitrate keeps more of the sound in a larger file. MP3 files are made with lamejs, a JavaScript port of LAME, under the GNU LGPL.
Or keep a WAV.
A WAV is not compressed again. It keeps the sound your browser decoded as 16-bit samples, in a much larger file than the MP3. Choose it if you will edit the recording.
From an iPhone
Get a voice memo off your iPhone.
Voice Memos keeps its recordings inside the app. Save one to Files first, then choose it on this page.
Open the memo in Voice Memos.
Tap the recording in the list so its controls show.
Tap the three dots, then Share.
On iOS 27, tap Options and choose Rendered, which makes a single .m4a file.
Choose Save to Files.
Pick a folder, such as On My iPhone, and tap Save. The memo is saved as an audio file, usually .m4a.
Choose it on this page.
Tap Choose a file at the top of this page and open the folder you saved it to.
These menus vary by iOS version, so the words on your phone may differ. A voicemail is saved from the Phone app instead: Save a voicemail shows how.
Questions
Before you convert.
Does converting M4A to MP3 lose quality?
A little. Both formats leave some sound out to save space. An M4A usually holds AAC sound that is already compressed, and the MP3 compresses it again in its own way. Use 192 kbps or more so the second step loses little, or save a WAV, which is not compressed again.
Can I just rename .m4a to .mp3?
No. Renaming changes only the name: the sound inside is still AAC, and some players and upload forms refuse it. Converting writes real MP3 sound.
How do I get a voice memo off my iPhone?
In Voice Memos, tap the recording, tap the three dots, then Share. On iOS 27, tap Options and choose Rendered first. Then choose Save to Files, and choose the saved file on this page. The menus vary by iOS version.
Which bitrate should I choose?
192 kbps is the default, and it is the lowest bitrate ACX accepts for audiobook MP3s. 256 or 320 kbps keeps more of the sound in a larger file. 128 kbps makes the smallest file and loses the most.
Will the MP3 sound clearer than the memo?
No. Converting changes the format, not the recording: background noise, hum or a muffled voice come through as they were. The check under the converter shows what it finds, and for a voice recording you can usually hear its first 20 seconds repaired.
Is my file uploaded?
Not to convert it. Your browser opens and converts the file on this device, and Solipsium's check of the recording runs in your browser too. Audio is sent only if you press Repair the first 20 seconds. For a mono or stereo recording of up to five minutes, only its first 20 seconds leave this browser; Solipsium repairs them on its server and deletes them within an hour. A longer file would have to go whole, so the try is offered for it only under 25 MB, and Solipsium keeps just its first 20 seconds.
Why will my M4A not open here?
Most M4A files hold AAC sound, which current versions of Chrome, Firefox and Safari open. An M4A saved in Apple's ALAC format opens only in Safari, so try Safari on a Mac or an iPhone. A recording longer than 30 minutes, or a file over 200 MB, is too large for this tool. If a voice memo will not open on your iPhone, save it to iCloud Drive and open this page on a computer.
Hard to hear the voice?
Drop a voice memo or voicemail on the family recordings page. The check runs in your browser, and you can hear its first 20 seconds repaired with no account.
Check a recording
The check and the 20-second try need no account.