Turn M4A files, such as iPhone voice memos and iTunes downloads, into MP3s that play on any device. Convert a whole batch at the bitrate you choose; everything runs on your device, so your audio is never uploaded.
MP3 quality
Advertisement
Advertisement
How to use the M4A to MP3
Add your M4A files: drop them on the box or click Choose M4A files. On iPhone, share voice memos to Files first, then pick them here.
Pick the MP3 quality: 192 kbps suits most music, 128 kbps mono is plenty for voice memos.
Optionally change channels or sample rate, or tick Normalize volume to make quiet recordings louder.
Press Convert to MP3. Each file shows its progress and new size.
Download each MP3, or press Download all (ZIP) to save the whole batch.
M4A vs MP3
Both formats are lossy, but they were designed a decade apart. AAC, the codec inside most M4A files, is generally more efficient: at the same bitrate it usually sounds as good as or better than MP3. MP3 wins on compatibility: every phone, car stereo, game console, DJ app and web service plays it.
M4A (AAC)
MP3
Standard
MPEG-4 Part 14 container with AAC (or ALAC) audio
MPEG-1/2 Audio Layer III
Typical bitrate
128 to 256 kbps
128 to 320 kbps
Size per minute at 256 kbps
about 1.9 MB
about 1.9 MB
Size per minute at 128 kbps
about 0.96 MB
about 0.96 MB
Plays on
Apple devices, modern Android, browsers
Practically everything
Common sources
iPhone Voice Memos, iTunes, Apple Music, screen recorders
Downloads, podcasts, music libraries
The file size depends only on the bitrate and length: size in bytes = bitrate (bits per second) ÷ 8 × duration (seconds). A 3-minute song at 192 kbps is 192,000 ÷ 8 × 180 = 4,320,000 bytes, about 4.3 MB.
Tips for the best MP3s
Match or exceed the source bitrate. iTunes music is usually 256 kbps AAC, so convert it at 256 or 320 kbps. Going higher than that does not bring back lost detail, it only makes the file larger.
Voice memos are mono. iPhone memos are recorded in mono, so choose Mono and 128 kbps (or even 96 kbps in the Audio Converter) for small, clear files.
Audiobooks (M4B) convert like any M4A, but chapter markers are not kept in MP3.
Normalize quiet recordings so they are as loud as possible without clipping.
Frequently asked questions
How do I convert M4A to MP3 for free?
Add your M4A files to this page, choose a bitrate such as 192 kbps and press Convert to MP3. The audio is decoded and re-encoded to MP3 in your browser, then you can download each file or a ZIP of all of them. There is no sign-up, watermark or upload.
What is an M4A file?
M4A is an MPEG-4 audio file, usually containing AAC audio. It is the default format for iPhone Voice Memos, iTunes and Apple Music purchases and many Android recorders. Some M4A files contain Apple Lossless (ALAC) audio instead of AAC.
Which bitrate should I choose?
Use 256 or 320 kbps for music from iTunes, which is usually 256 kbps AAC, to keep as much quality as possible. Use 192 kbps for everyday music and 128 kbps, ideally in mono, for voice memos, lectures and podcasts.
Does converting M4A to MP3 lose quality?
Both AAC and MP3 are lossy, so re-encoding loses a little detail. At 256 or 320 kbps the difference is very hard to hear. MP3 is still the most compatible format for older players, car stereos and some apps.
Why can't my M4A file be converted?
Files bought from iTunes before 2009 may be DRM-protected .m4p files, which cannot be converted. Apple Lossless (ALAC) M4A files only decode in Safari. Most other browsers decode AAC M4A files without problems.
Can I convert iPhone voice memos to MP3?
Yes. In the Voice Memos app, tap the memo, choose Share and Save to Files, then open this page in Safari and choose the saved .m4a file. Mono at 128 kbps keeps the files small while keeping speech clear.
Are my files uploaded to a server?
No. The conversion runs entirely in your browser using the Web Audio API and the LAME MP3 encoder compiled to JavaScript, so your recordings never leave your device.