M4A to MP3 converter

Mostly iPhone and Mac owners. Voice Memos, the Music app and songs bought from the iTunes Store all give you M4A files, and plenty of things still want MP3: an older car stereo or MP3 player, a podcast host or course platform with an MP3-only upload, a DJ or audio app, a family member’s laptop. A voice memo you need to send somewhere is the most common case; a playlist of iTunes songs for a device that will not read AAC is the next.

M4A is not a codec of its own. It is the MP4 format with the picture left out, and the “a” stands for audio: rename one to .mp4 and most players open it unchanged. Inside there is almost always AAC, the sound format Apple uses for iTunes, Apple Music downloads and Voice Memos, and now and then Apple Lossless.

The trouble is the long tail of things built before AAC was common. Older car stereos and MP3 players, some podcast and course upload forms, DJ software and a few Windows and Android apps accept only MP3, and some show an M4A as an unknown file. MP3 has been the default for so long that it plays on almost anything with a speaker, which is the whole reason to convert.

The bitrate sets the size and how much detail survives. As a guide, 128 kbps is about 1 MB a minute, 192 kbps about 1.4 MB and 320 kbps about 2.4 MB.

• 128 kbps for voice memos, lectures, podcasts and other speech. A voice memo is usually well under that already, so a higher setting only makes the file bigger, and the converter says so when it sees one.
• 192 kbps, the default, for music from the iTunes Store or Apple Music app. It keeps nearly all of a 256 kbps song at about three quarters of the size.
• 320 kbps when the original is lossless or high quality and space does not matter: a DJ set, a file you will edit further, a car stereo you listen to loud.

Songs bought from the iTunes Store since early 2009 are ordinary AAC files in M4A with no copy protection, so they convert like any other. The title, artist, album and cover art come across into the MP3’s ID3 tags.

Songs bought before then were sold as Protected AAC, usually with the extension .m4p, and songs downloaded through an Apple Music subscription are protected too. No converter can read them without removing the protection, so this page names the problem instead of failing halfway. For a purchased song, download it again from your iTunes Store purchases: the copy you get now has no protection.

If the device or app already plays M4A, keep the M4A. iPhones, Macs, Android phones, Windows’ Media Player and most newer car systems all play AAC, and at the same size it sounds a little better than MP3. Converting only to be safe costs some quality for nothing.

Converting cannot rescue a poor recording: a quiet, muffled or noisy voice memo becomes a quiet, muffled or noisy MP3. And if you have the song on CD or in Apple Lossless, make the MP3 from that rather than from an AAC copy, so it is converted once instead of twice.